So it's the palm software instead of the windows software right? I don't know a whole lot about the Palm software, I mean I sell them, but all my phones have been windows. Handago.com sells a lot of programs for treo's, but you have to pay for those. You might want to try ppcgeeks.com. They have a forum where people post all kinds of programs, wallpapers, games, themes, everything. That's about the best I've found. I put the threaded text messaging that the palm's have on my windows HTC and it's great. Also got picture speed dials on my home screen. That's awesome to. Just go up there and browse around.
Treat it just like this forum. Browse around, see if they got what you like. Search that forum. I have never posted anything in there, you can find anything you need just by looking arount. Don't jump in as a newb and make your first post about something that is already on that page. If you can get it, they already have it.