iOS 4.1 Beta was seeded to developers yesterday. Since the iOS 4.1 is currently only jailbreakable on iPhone 3G and iPod touch 2G (non-MC model), you may want to downgrade your other iOS based devices from iOS 4.1 so that you can jailbreak them on iOS 4, or iOS 3.1.3 / 3.1.2 (formerly iPhone 3.1.3 or 3.1.2).
The following step by step guide will help you rollback / downgrade to iOS 4, iPhone 3.1.3 and 3.1.2 from iOS 4.1 Beta as long as you have SHSH blobs saved for the respective firmwares for iPhone 4, iPhone 3GS, iPhone 3G and iPod touches.
