Thanks Dorris, I went with something similar:

	lcCentury = SET('CENTURY')
	lxThisValue = IIF(TYPE('THIS.Value')='T', ;
		TTOD(THIS.Value), THIS.Value)

	SET CENTURY ON
	lxDateValue = IIF(TYPE('lxThisValue')='T', GETaDATE(), GETaDATE("D"))
	SET CENTURY &lcCentury


	*--Check for future date
	IF lxThisValue > lxDateValue
		ldStartValue = this.value
		TRY
			IF TYPE('this.value') = 'T'
				THIS.value = DTOT(CTOD(STR(MONTH(this.value))+'/'+STR(DAY(this.value))+'/'+STR(YEAR(this.value)-100)))
			ELSE
				THIS.value = CTOD(STR(MONTH(this.value))+'/'+STR(DAY(this.value))+'/'+STR(YEAR(this.value)-100))
			ENDIF
		CATCH 
			THIS.value = ldStartValue
			RETURN .F.
		ENDTRY
		IF TYPE("gluse2DigYear")="L" AND gluse2DigYear
			SET CENTURY OFF
		ENDIF
		RETURN .T.
	ENDIF

>If Century is set on, don't they have to enter a 4 digit year?
>
>otherwise, are you looking for something like:
>
>if Year(dtofBirth) > Year(date())
> dtofBirth = ctod(alltrim(str(Month(dtofBirth))) + ;
> alltrim(str(Day(dtofBirth))) + ;
> alltrim(str(Year(dtofBirth)-100)))
>endif
>
>>A user can enter 2 or 4 digit value for the year section in a datetime field: (i.e. 01/01/01 or 01/01/2001)
>>
>>1. If the year is in the future, invalid - set to same date in previous century (i.e. 08 entered, make it 1908, or 2008 entered, make it 1908).
>>2. If the year is between the current century and the current year (2000/00 to 2007/07), assume this century.
>>3. If the year is greater than the current year, set it to the same date in the previous century.
>>
>>For some reason I am not getting this today. It should be so very very simple...