Saurik has upgraded Cydia to be compatible with 3.0 OS ready for the official release. Several things to note before you go ahead and start using the latest unofficial QuickPWN release below to jailbreak: The QuickPWN jailbreak only patches codesign_, i.e. it only utilizes one of a total three essential kernel patches, meaning that the jailbreak is unstable and there will be problems with many jailbreak applications. Saurik has stated that, as far as he knows, Winterboard IS compatible with 3.0 but the lack of the two additional kernel patches means it won't work with this current jailbreak. The 3.0 is beta still thus there is very little point in upgrading and jailbreaking, uınless you are a developer looking to test on this platform. For everyone else, wait another month or so for the official 3.0 OS release. This QuickPWN + 3.0 Cydia release only works on the 3G iPhone (work by lilstevie & Hozy), 2G iPhone & 1G iPod Touch (work by iphoneapps.ru). If you do upgrade your 3G iPhone to 3.0 beta 5 remember that you will also upgrade your baseband to the latest unhacked version and thus will kill any chance of downgrading your baseband and/or unlocking for other operators with yellowsn0w. The DevTeam have stated that any official FULL 3.0 jailbreak and official QuickPWN GUI will only be released once the 3.0 OS has been officially released. If you still want to try Cydia out on 3.0 beta 5 here is a link to an upgraded unofficial QuickPWN release that includes the Cydia 3.0 payload: Unofficial QuickPWN w/ Cydia payload [credit: HoZy and lilstevie] Note that I haven't and won't be testing this. I'm just putting it up for the community to have a look at. Thanks to lilstevie for his input in the thread here.