I put it on ebay here:
Palm Treo Pro 850 GSM AT&T T-Mobile UNLOCKED Smartphone - eBay (item 200338165063 end time May-07-09 18:00:00 PDT)

I bought it 2 months ago. It is in perfect condition. My fingers are just too big for it's tiny keyboard.
I bought an extra stylus and AC charger, that I will include.