I just bought an iphone a couple days ago (1-13-08) and I've successfully unlocked (jailbroke) the phone.
Here is the site, you will need access to a mac as the iNdependence program is mac only.
http://www.iphoneatlas.com/2007/11/30/foolproof-or-close-to-it-iphone-112-jailbreak/I purchased a sim chip to mod my own sim card and will have that tomorrow, but I have successfully unlocked my phone. (I took me about 6 hours until I found this site with it's step by step instructions that helped.)
I will post again after I try my sim chip tomorrow. I purchased my sim chip mod from
www.i3gsim.com