Sn0wbreeze V1.6 has been Released minutes ago to Jailbreak iPhone 3GS, iPhone 3G, iPod 2G on iOS 4 for Windows users, Now I tried it and it's working on Windows, So if you didn't jailbreak yet (or don't know how) here's the step by step guide posted below.. Steps: Step 1: Download and Install iTunes 9.2 from Here. Step 2: Now Start iTunes, then Back up all your Data by Right click on iPhone (on right side of iTunes) then Click on Backup Step 3: Download Sn0wbreeze V1.6 from Here , iOS 4 original firmware from Here, and Download .NET Framework 3.5 (required to run Sn0wbreeze) from Here. Step 4: Start Sn0wbreeze and Select "Simple Mode" Step 5: Click browse and select the iOS 4 firmware that you had downloaded for your iPhone. Step 6: Now, if you selected the right firmware, Sn0wbreeze will show you the following page, Click on the blue arrow Step 7: Sn0wbreeze will asks you if you have activated iPhone click on "Yes Step 8: Now Sn0wbreeze should creat your Custom Firmware Step 9: Now Sn0wbreeze should Done with the Custom Firmware as the following Step 10: Once the .ipsw file created, navigate to itunes, Click on iPhone on the left, then hold left alt button (Shift button on Windows) on the keyboard and then click on Restore then release the alt button Step 11: iTunes now should ask you about the .ipsw file, head up it to the created custom firmware by Sn0wbreeze Step 12: Now, Sit back and let iTunes do it.. After several steps of installing the new firmware, Your device should be Jailbroken Successfully Note: If you will Jailbreak on iPhone 3GS then you should have Old bootrooms ONLY, not new! Answering a reader who asked To know the type of your Bootroom follow the guide below: Step 1: On your iPhone, go to Settings>General and tap on About. Step 2: Look for Model in the list. If your iPhone model number starts with MC, then youve got new bootrom (MC model), if it doesnt start with MC, youve got old bootrom (non-MC model). Now, You will be Easily able to Unlock your iPhone 3GS on any Baseband Including 05.13.04 / 05.12.01 Using Ultrasn0w 0.93, Step by Step guide posted here.