The title says it all. The popular unlocking tool for iPhone 3GS, 05.11.07 baseband on iPhone 3.1.3/3.1.2 has been successfully ported to work with the latest iPhone OS 4 Beta 4. This port is based on the binaries provided by msft.guy and the original blacksn0w unlock by Geohot.

If you are an expert user, you can give this one a go! But we will highly recommend you to stay away as the official unlock by iPhone Dev Team for iPhone 3.1.3, 05.12.01baseband will be out as soon as Apple releases the next iPhone along with final version of iPhone OS 4.

Instructions for unlocking iPhone 3GS with 05.11.07 baseband on iPhone OS 4 Beta 4 can be seen in the video attached below.