Infinite Disorder

Even though the OS just came out, this is actually a very easy mod. I just downloaded the files from http://www.iclarified.com/entry/index.php?enid=4255
You use the Pwnage.app to create a new firmware file (.ipsw) and then restore the file to your phone. Once the firmware has loaded, it will reboot and update the baseband (be patient). Pwnage has come a long way since the release of the iPhone, the GUI is quite nice now. The downloads take about 20 minutes and the upgrade itself will run you another 20 minutes.
To test, throw in a prepaid T-mobile SIM and make a call. If you put an apple account into the App store, you can download apps- but only over wifi; the SIM I was using didn’t allow any data transfer over EDGE, I’m not sure if those are available in the US or not.