I've noticed that their are a lot of people still looking around the boards for how to upgrade their 1.0.2 phones. Their isn't a guide listed here in the MMi guides section that uses the installer source for virginizing, instead it uses terminal, which some users may not like.
Here is a link with instructions to virginize and restore to 1.1.1:
http://iphone.unlock.no/

It also has info on how to jailbreak and unlock the 1.1.1,
but if you would like to goto 1.1.2, use this guide just to get you to 1.1.1 and then use the guides here on MMi to get you to an unlocked 1.1.2