Just a few days after Apple released an updated iPhone OS 3.1.3, the jailbreaking software followed suit by releasing updates that would allow users to jailbreak and unlock their iPhone. Earlier released redsn0w was not able to jailbreak iPhone 3G and 3GS, however, updated versions of blacksn0w, ultrasn0w and sn0wbreeze do.
There is some good news for iPhone 3G and 3GS users as they will now be able to Jailbreak and unlock their phones using either blacksn0w, ultrasn0w and sn0wbreeze. Users can now unlock their iPhone 3G or 3GS with ultrasn0w for 04.26.08 baseband or blacksn0w for 05.11.07 baseband.
The crowd favorite unlocking and jailbreaking software blackra1n, which is written by George Hotz is not yet able to jailbreak or unlock iPhone using the new iPhone OS 3.1.3, so if you are a blackra1n user, you will have to wait for a few more days before you can see an update.
For instructions on jailbreaking and unlocking your iPhone 3G and 3GS visit Redmond Pie, who have complete step by step instructions on executing the jailbreak and unlocking using blacksn0w, ultrasn0w and sn0wbreeze.