After few minutes of launch of iOS 5 Gold Master version for developers, MuscleNerd has confirmed through a tweet that it can be JailBroken using latest version of Redsn0w. However, you will require to point out iOS 5 Beta 7 on it for the process to move ahead. Once done, you would get a JailBroken iOS 5 GM version. As usual, it a tethered JailBreak.
Tethered JailBreak means that you need to connect to PC/Mac every time the battery dies. If you just boot up directly, you would face several problems with your device. It may also lead you to restore the firmware again. Also, it is expected that untethered JailBreak which would be based on userland exploit will be released after iOS 5 final.
Apple has announced that iOS 5 final will hit iTunes on October 12 which is not too far. Only developers are requested to restore their device using beta firmwares. Otherwise, you may face serious issues.