There was last night released a new version of redsn0w, which jailbreak iOS 5 .0.1 possible. The iPhone Dev Team warns sure that there is still a tethered jailbreak. Only iPhone 3G owners who still use the old bootrom can run untethered jailbreak.
The update of RedSn0w solve the problems that had to jail breakers with iBooks. The fix is specifically applied in which the sandbox mechanism around it is removed. Have you performed a jailbreak, you can apply this fix without having to re-jailbreak using redsn0w by installing Cydia and unchecking.
Windows users may like OSX users can now also custom IPSW's generation with redsn0w, similar to the functionality PwnageTool and sn0wbreeze offer. These custom firmwares carry no baseband update with it.
The iPhone Dev Team warned iPhone 3G users on newer flashing the iPhone with the iPhone baseband. This would be for the iPhone owners are not possible. If your iPhone 3G's serial number begins with xx135, you fall under this group.