I may be a bit confused. I am using a program iTSFv to copy my iTunes Ratings and Playcount to from the XML database into the PCNT and POPM fields in the music files (or that is my understanding). I was wanting to confirm this by using MP3tag to view these fields, however when I went to add them to the display they are not listed under the PCNT or POPM headings. Does anyone know what fields I am looking for?

I can only refer you to the online help, Topic "Names and mapping of ID3v2/WMA/MP4 tag fields"

It states that POPM is mapped to %POPULARIMETER%. The other one I guess ist the play counter which is part of %POPULARIMETER%.
THis is, what the online help tells us:
"This description is for only ID3v2 tags. The playcounter is an optional value.

Syntax: Email|Rating|Playcounter
Example: Mp3tag|255|5
Note: The Rating is an integer between 0 (worst) and 255 (best)."

BTW: you know that iTunes does not read this field back but stores any ratings only in the local database - WMP on the other hand does evaluate the field and displays the right amount of golden stars.
But perhaps your tool is so versatile that it updates the iTunes database.