i used to have a palm pre and found it easiest to just drag and drop files (not a fan of itunes!) however see this thread as they mention issues and possible work arounds to it.
have you got the preware app? its sort of like cydia for palm pre's with loads of customisation options and handy utilities such as an app which puts your phone into airplane mode at a set time and wakes it up at another (so you dont get interrupted during sleeps time!) also the gbc emulator (visualboy advance) is on there and whilst gba files are a little slow, gbc files work really well, i had pokemon red on it. all controlled with the keyboard.
i recommend pre central for tips tricks etc, helped me out alot when i was using my pre.