well, as long as you have a data plan, you should be fine. I would start
here, its a long thread, but deals particularly with PAM on the TP. Now, you can try this fix here,
post 95-97, the instructs are in those posts, however, I only tried this on the Treo 800w(it lets u use your regular username, instead of a PAM username). But if you need any more help with this, jus PM me, i help the best way i can