download the custom firmware from here:
http://www.ilikemyiphone.com/2009/0...e-ipsw-files-for-iphone-2g-3g-3-1-windowsmac/
and connect your itunes in recovery mode.. in itunes hold down shift and click restore.. a dialog box pops up asking for the firmware.. give it the link to the downloaded custom firmware and voila your iphone is jailbreaked + unlocked and running with fw 3.1..
search google for 'iphone firmware 3.1 jailbreak windows' for further assistance.. because i have done this on a lot of iphones and it works, but i used some other website not the one i have linked and i cant seem to find it right now.. but the methods the same so dont worry..
edit: just noticed its 3.1.2.. the firmware restore might enable your phone, but the baseband would be different so you wouldnt be able to call most probably.. anyways best of waiting for 4th november..