The iPhone Dev Team has updated Redsn0w to 0.9.9b6 which now offers quick jailbreaking iOS 5 on Windows. Usually you have to download the entire iOS 5 firmware manually then pre select it in redsn0w to jailbreak, the new update skips that and does it for you.
This new update also fixes location services for those having problems. Just rerun Redsn0w over your current jailbreak if having problems and uncheck all of the boxes including install Cydia.
Download Redsn0w 0.9.9b6:
We’ve released version 0.9.9b6 of redsn0w, with both a functional fix and cosmetic fix for iOS5 jailbreakers. For iPhone3GS owners with the 06.15 baseband, this redsn0w eliminates the network crash you saw when using Location Services in iOS5 (in fact, you don’t even need to disable Location Services anymore during the initial setup). The cosmetic fix is to the visual countdown you see when going into DFU mode.
It’s okay to re-run this redsn0w over an existing device jailbroken at iOS5. Just choose “Jailbreak” again and de-select Cydia (in other words, all the checkboxes will be unchecked). If you are lucky enough to have an old-bootrom iPhone3GS, please pre-select the IPSW first (redsn0w can’t yet auto-detect the FW version of your old-bootrom 3GS if it’s already been jailbroken).