The official ultrasn0w unlock has been released by iPhone Dev Team for iPhone 3GS, with older bootrom running 04.26.08 baseband on iOS 4.0 (formerly iPhone OS 4). For those of you who preserved their baseband by jailbreaking iPhone 3GS on iOS 4 using PwnageTool can now unlock, provided that your phone is running the older 04.26.08 baseband.
Good news for those of you who are in UK, France and Canada. iPhone 4 in these countries are available without contract, which means that it is unlocked so that you can use it with any carrier you want - anywhere in the world. These SIM free unlocked iPhone 4’s are available for £499 for the 16GB model, and £599 for the 32GB model in the UK, €629 for 16GB and €739 for the 32GB in France, and $649 for the 16GB and $749 for the 32GB in Canada.
Now that we have a jailbreak (developers only) for iPhone OS 4 Beta, and an upgraded version of Fuzzyband (Baseband downgrader). Technically, iPhone 3G can now be unlocked on the latest iPhone OS 4 Beta, provided that you have one of those rare iPhone 3G’s with 05.08 bootloader that is downgradable to 05.13.03 baseband of OS 4 to 04.26.08 so that ultrasn0w can unlock it.