It's simpler than you think.

cValue = "JA0000165801"
oIE = CREATEOBJECT("InternetExplorer.Application")
oIE.Navigate("http://www.fastway.com.au")
IF WaitForReadyState(oIE)
        oIE.Document.FTrace.TAG.value = ALLTRIM(cValue)
        oIE.Document.FTrace.Submit()
        oIE.Visible = .t.
ELSE
        MESSAGEBOX("Internet Connection timed out",64,"Apparently no Internet Connection")
ENDIF 

oIE = null

The WaitForReadyState function can be found by searching for SmartSMS on the fox wikis.
Basically, this code opens up an instance of IE. Waits for it to be ready. Inserts the value in the field and then submits the form. Normally, cValue should come from another source (not hard coded :-))
To understand this fully, you should 'view' the source on that website page.

Hope this helps

Peter Easson