I would suggest you do what guha mentions. It is preferable to use the functions offered within the application to do the dirty worked, it will simplify your code and the functions will probably be optimized for the applications.

Anyway if you still want to know what the page number is use:

Either
Selection.Information (wdActiveEndPageNumber)
or
Selection.Information (wdActiveEndAdjustedPageNumber)

This was found on a quick google. You may want to do your own search because MS had some problems with these and they have suggestions for word 2000