if you liked ff tactics advance you should try Tactics Ogre, same thing with more depth and a serious story:
http://www.youtube.com/watch?v=ocFJOjvnz5Q
FF tactics for PSP will be released October (U.S and Europe), but you probably know that:
http://www.youtube.com/watch?v=oxaqwkpe_Pw
...other than that, theres no other good strategy rpg for PSP that i know of.
