DO NOT ATTEMPT THIS UNLESS YOU HAVE 4.1 BETA 3. DO NOT UPDATE TO 4.1 IF YOU WANT TO JAILBREAK. IT PRETTY MUCH BUSTS EVERYTHING. PLEASE WAIT FOR A NEW JAILBREAK. Requires: iTunes 10.0 (9.2.x is fine) iOS 4.0 and 4.1 IPSWs redsn0w ( Mac - Windows ) iPod Touch 2G MB iPhone 3G (if you wanna risk losing unlock) 1. Update iTunes to 10.0 and restore your device to 4.1. 2. Execute redsn0w and select the iOS4.0 ipsw. 3. Select Install Cydia. You may also want custom boot/recovery logos, and multitasking, homescreen backgrounds, and battery, so select that too if you like. 4. Plug in your device, turn it off, and click next. Be prepared to enter DFU mode. 5. Follow the onscreen instructions. Press power, then home, and release power while still pressing home, in the presented times. 6. Let redsn0w do all the work. You have jailbroken your device. Have fun! (Source) THIS IS AN UNSTANBLE JB. According to HB10MUFC, the Phone app goes away and the Cydia app loads with a ton of errors. Wait for b6 to come out.