Me thinks I found a clue to what PP is...
Found this on a FFX1 website
Preserved Chokidai Vocal Cords 175000 pp
Lockjaw Hide Vest 1000 pp
Blood Point 800 pp
Scepter of Rahotep 10000 pp
It sounds like a money along the lines of GP from the Gold Saucer or a unit of measure on how good something is like our RPG's buff. stat.
Don't forget to look above at Squall's post.
EDIT:
I just started having some problems with the RPG thing. About every 11 or so battles it freezes. My anti-virus stuff pops up saying "This program is not responding" and gives me the option to turn it off. This takes about 5 minutes so I was wondering if this is just my computer or is the RPG not working right?