remote erase on broker iphone 3g

Hi
My iphone 3g broke - I tried to restore it but I get the white screen of death!
Since then, I got a new phone but I now want to sell my old one. However, I dont want to sell it as it is because my numbers / calendar / messages/ photos will still be in the memory.
Is there any way I can erase all the details in the phone (from itunes) so that I can sell it safely?
Someone suggested I set up a new profile in Vista, sign up to itunes as a new user and ensure that when I go to sync it, nothing is synced (because there would be no music etc in my account)?
I cannot erase all contents on the phone itself because I cant get passed the white screen!
thanks
toshiba laptop Windows Vista