I believe Sergey posted this a while back.

#DEFINE DC_PAPERS     2 
#DEFINE DC_SIZE       8 
#DEFINE DC_VERSION    10 
#DEFINE DC_PAPERNAMES 16 

DECLARE INTEGER DeviceCapabilities IN winspool.drv; 
    STRING pDevice, STRING pPort, INTEGER fwCapability,; 
    STRING @pOutput, INTEGER pDevMode 

LOCAL lcBuffer, lnCount, lnIndex, lcName 
lcBuffer = Repli(Chr(0), 16384) 

* provide valid printer and port names 
lcprinter = GETPRINTER()

lnCount = DeviceCapabilities(lcprinter, "",; 
    DC_PAPERNAMES, @lcBuffer, 0) 

* each string buffer is 64 characters long 
* and contains the name of a paper form 
ACTIVATE screen
llfoundit = .F.
FOR lnIndex=1 To lnCount 
    lcName = SUBSTR(lcBuffer, (lnIndex-1)*64+1, 64) + Chr(0) 
    lcName = SUBSTR(lcName, 1, AT(Chr(0), lcName)-1) 
    IF UPPER(ALLTRIM(lcName))='DBMEMO'
        llfoundit = .T.
    ENDIF
    ? lcName 
ENDFOR 

IF !llfoundit
    ooo = NEWOBJECT("AddPrinterForm")
    IF NOT ooo.AddForm("DBMEMO", 5,7, lcPrinter)
          * Error
        lcmessage= ooo.cErrorMessage
        lcmessage=lcmessage+CHR(13)+ooo.cApiErrorMessage 
        =MESSAGEBOX(lcmessage,0+16+4096,'An Error Ocurred.')
    ENDIF
    ooo = Null
ENDIF

RETURN




* All sizes in inches
ooo = NEWOBJECT("AddPrinterForm", "AddPrinterFormClass")
IF NOT ooo.AddForm("MyCustomForm1", 5,7, "EPSON Stylus C82 Series")
    ? ooo.cErrorMessage
    ? ooo.cApiErrorMessage 
  * Error
ENDIF
ooo = Null
*RETURN
* All sizes in cm
ooo = NEWOBJECT("AddPrinterForm", "AddPrinterFormClass.fxp", "", "Metric")
IF NOT ooo.AddForm("MyCustomForm2", 15,17, "EPSON Stylus C82 Series")
  * Error
ENDIF
ooo = Null

ooo = NEWOBJECT("AddPrinterForm", "AddPrinterFormClass.fxp")
IF NOT ooo.DeleteForm("MyCustomForm1", "EPSON Stylus C82 Series")
    ? ooo.cErrorMessage
    ? ooo.cApiErrorMessage 
  * Error
ENDIF
*AddPrinterFormClass.prg
DEFINE CLASS AddPrinterForm AS Custom

    HIDDEN cUnit, cPrinterName, nFormHeight, nFormWidth, nLeftMargin, ;
              nTopMargin, nRightMargin, nBottomMargin, ;
          nInch2mm, nCm2mm, nCoefficient, hHeap

    cUnit = "English"        && inches or Metric - cm's
    cPrinterName = ""
    nFormHeight = 0
    nFormWidth = 0
    nLeftMargin = 0
    nTopMargin = 0
    nRightMargin = 0
    nBottomMargin = 0

    nApiErrorCode = 0
    cApiErrorMessage = ""
    cErrorMessage = ""

    nInch2mm = 25.4
    nCm2mm = 10
    nCoefficient = 0

    hHeap = 0

    PROCEDURE Init(tcUnit)
    IF PCOUNT() = 1 AND INLIST(tcUnit, "English", "Metric")
        This.cUnit = PROPER(tcUnit)
    ENDIF
    This.LoadApiDlls()
    This.hHeap = HeapCreate(0, 4096, 0)
    * Use Windows default printer
    This.cPrinterName = SET("Printer",2)
    This.nCoefficient = IIF(PROPER(This.cUnit) = "English", ;
        This.nInch2mm, This.nCm2mm) * 1000
    ENDPROC

    PROCEDURE Destroy
    IF This.hHeap <> 0
        HeapDestroy(This.hHeap)
    ENDIF

    ENDPROC

    PROCEDURE SetFormMargins(tnLeft, tnTop, tnRight, tnBottom)
    WITH This
        .nLeftMargin     = tnLeft   * .nCoefficient
        .nTopMargin     = tnTop    * .nCoefficient
        .nRightMargin     = tnRight  * .nCoefficient
        .nBottomMargin     = tnBottom * .nCoefficient
    ENDWITH
    ENDPROC

    PROCEDURE AddForm(tcFormName, tnWidth, tnHeight, tcPrinterName)
    LOCAL lhPrinter, llSuccess, lcForm

    This.nFormWidth  = tnWidth  * This.nCoefficient
    This.nFormHeight = tnHeight * This.nCoefficient
    IF PCOUNT() > 3
        This.cPrinterName = tcPrinterName
    ENDIF

    This.ClearErrors()
    lhPrinter = 0
    IF OpenPrinter(This.cPrinterName, @lhPrinter, 0) = 0
        This.cErrorMessage = "Unable to get printer handle for '" ;
                                + This.cPrinterName + "."
        This.nApiErrorCode = GetLastError()
        This.cApiErrorMessage = This.ApiErrorText(This.nApiErrorCode)
        RETURN .F.
    ENDIF

    lnFormName = HeapAlloc(This.hHeap, 0, LEN(tcFormName) + 1)
    = SYS(2600, lnFormName, LEN(tcFormName) + 1, tcFormName + CHR(0))

    * Build FORM_INFO_1 structure
    WITH This
        lcForm = This.Num2LOng(0) + ;        && Flags
        This.Num2LOng(lnFormName) + ;
            This.Num2LOng(.nFormWidth) + ;
            This.Num2LOng(.nFormHeight) + ;
            This.Num2LOng(.nLeftMargin) + ;
            This.Num2LOng(.nTopMargin) + ;
            This.Num2LOng(.nFormWidth - .nRightMargin) + ;
            This.Num2LOng(.nFormHeight - .nBottomMargin)
    ENDWITH

    * Finally, call the API
    IF AddForm(lhPrinter, 1, @lcForm) = 0
        This.cErrorMessage = "Unable to Add Form '" + tcFormName + "'."
        This.nApiErrorCode = GetLastError()
        This.cApiErrorMessage = This.ApiErrorText(This.nApiErrorCode)
        llSuccess = .F.
    ELSE
        llSuccess = .T.
    ENDIF
    = HeapFree(This.hHeap, 0, lnFormName)
    = ClosePrinter(lhPrinter)

    RETURN llSuccess

    PROCEDURE ClearErrors
    This.cErrorMessage = ""
    This.nApiErrorCode = 0
    This.cApiErrorMessage = ""
    ENDPROC

    PROCEDURE DeleteForm(tcFormName, tcPrinterName)
    LOCAL lhPrinter, llSuccess

    IF PCOUNT() > 1
        This.cPrinterName = tcPrinterName
    ENDIF

    This.ClearErrors()
    lhPrinter = 0
    IF OpenPrinter(This.cPrinterName, @lhPrinter, 0) = 0
        This.cErrorMessage = "Unable to get printer handle for '" + This.cPrinterName + "."
        This.nApiErrorCode = GetLastError()
        This.cApiErrorMessage = This.ApiErrorText(This.nApiErrorCode)
        RETURN .F.
    ENDIF

    * Finally, call the API
    IF DeleteForm(lhPrinter, tcFormName) = 0
        This.cErrorMessage = "Unable to delete Form '" + tcFormName + "'."
        This.nApiErrorCode = GetLastError()
        This.cApiErrorMessage = This.ApiErrorText(This.nApiErrorCode)
        llSuccess = .F.
    ELSE
        llSuccess = .T.
    ENDIF
    = ClosePrinter(lhPrinter)
    RETURN llSuccess

    FUNCTION Num2LOng(tnNum)
    DECLARE RtlMoveMemory IN WIN32API AS RtlCopyLong ;
        STRING @Dest, Long @Source, Long Length
    LOCAL lcString
    lcString = SPACE(4)
    =RtlCopyLong(@lcString, BITOR(tnNum,0), 4)
    RETURN lcString
    ENDFUNC

    FUNCTION Long2Num(tcLong)
    DECLARE RtlMoveMemory IN WIN32API AS RtlCopyNum ;
        Long @Dest, String @Source, Long Length
    LOCAL lnNum
    lnNum = 0
    = RtlCopyNum(@lnNum, tcLong, 4)
    RETURN lnNum
    ENDFUNC

    HIDDEN PROCEDURE ApiErrorText
        LPARAMETERS tnErrorCode
        Local lcErrBuffer
        lcErrBuffer = REPL(CHR(0),1024)
        = FormatMessage(0x1000 ,.NULL., tnErrorCode, 0, @lcErrBuffer, 1024,0)
        RETURN STRTRAN(LEFT(lcErrBuffer, AT(CHR(0),lcErrBuffer)- 1 ), ;
                         "file", "form", -1, -1, 3)

        ENDPROC

    HIDDEN PROCEDURE LoadApiDlls
        DECLARE INTEGER OpenPrinter IN winspool.drv;
            STRING  pPrinterName,;
            INTEGER @phPrinter,;
            INTEGER pDefault
        DECLARE INTEGER ClosePrinter IN winspool.drv;
            INTEGER hPrinter
        DECLARE INTEGER AddForm IN winspool.drv;
            INTEGER hPrinter,;
            INTEGER LEVEL,;
            STRING  @pForm
        DECLARE INTEGER DeleteForm IN winspool.drv;
            INTEGER hPrinter,;
            STRING  pFormName 
        DECLARE INTEGER HeapCreate IN Win32API;
            INTEGER dwOptions, INTEGER dwInitialSize,;
            INTEGER dwMaxSize
        DECLARE INTEGER HeapAlloc IN Win32API;
            INTEGER hHeap, INTEGER dwFlags, INTEGER dwBytes
        DECLARE lstrcpy IN Win32API;
            STRING @lpstring1, INTEGER lpstring2
        DECLARE INTEGER HeapFree IN Win32API;
            INTEGER hHeap, INTEGER dwFlags, INTEGER lpMem
        DECLARE HeapDestroy IN Win32API;
            INTEGER hHeap
        DECLARE INTEGER GetLastError IN kernel32
        Declare Integer FormatMessage In kernel32.dll ;
            Integer dwFlags, String @lpSource, ;
            Integer dwMessageId, Integer dwLanguageId, ;
            String @lpBuffer, Integer nSize, Integer Arguments

        ENDPROC

ENDDEFINE

>Is there any way to add new printer form size in XP from VFP program.
>Rajesh