You can safely update to the newest iOS beta but ONLY if you have an MB model device (iPhone 3G and iPod Touch 2g MB). Do NOT update if you have an MC Model device. The current version of redsn0w (v0.9.5b5-5) can jailbreak iOS4 beta 1. Follow part B of this guide: http://www.ifans.com/forums/showthread.php?t=299443 THAT GUIDE DOES NOT WORK. WILL POST ANOTHER GUIDE MYSELF. You cannot jailbreak if you have an MC model device since sn0wbreeze has not been updated. Sign up for Apple's developer program to grab the 4.1 beta: http://developer.apple.com/iphone/index.action Safely update to iOS4.1 beta when jailbroken: http://www.ifans.com/forums/showthread.php?t=294917 Even though the guide says iOS4.0, it works with all firmwares. You just have to follow the instructions on the bottom of the first post. New Features of iOS4.1b1 are: Much improved Game Center Standard cleanup (Speed enhancements and such) Taller signal bar pictures: (in iOS 4.0.1 update) Please Register or Log in to view images Flash/Camera buttons reposition in landscape. Favorites in the Phone application can be added as voice or FaceTime. Check Spelling can be turned Off in Settings. Fixes signal detection to make bars more accurate. (in iOS 4.0.1 update) Baseband has been updated to 02.07.01 (kills unlock). And no. It unfortunately does not fix the bad signal on the iPhones. EDIT: iOS 4.0.1 official has been released (currently only for iPhone)! iPad OS 3.2.1 has also been released (kills Spirit)! 3.2.1 fixes iPad wifi issues. 4.0.1 does the taller signal bars, and does the better signal accuracy. It can still be jailbroken with redsn0w 0.9.5b5-5.