Finally GeoHot released PurpleRa1n to Jailbreak iPhone 3G S OS 3.0 All you have to jailbreak is just download a small 350KB PurpleRa1n.exe (Windows Only). Connect your iPhone 3G S and hit the make it ra1n button and voila your iPhone is jailbreaked. You don’t need any iBEC and iBSS signature files for jailbreaking your iPhone 3GS OS 3.0 but make sure to capture these files for upcoming OS 3.1 jailbreak. PurpleRa1n doesn’t need to put your phone in DFU mode, you don’t need firmware. Just a simple click will take care of your Jailbreak process.
Earlier today Planetbeing iPhone Dev team member and the mind behind Linux on iPhone demonstrated the first iPhone 3G S unlock with Ultrasn0w. Check the video iPhone 3GS Unlock With Ultrasn0w Successful
Step 1) Make sure you have latest version of iTunes and Purplera1n works best on Windows XP and Windows Vista. Peoples running on Windows 7 should stay away for a while or borrow your friends XP/Vista Machine.
Step 2)for Windows and launch the program. Make sure your iPhone 3G S is connected to computer.
Step 3) Hit the Make it Rain button and open your umbrella.
For Step by Step visual : Guide to Jailbreak your iPhone 3GS with Purplera1n