The iPhone Dev Team has released an update to the iPhone unlock ultrasn0w, version 1.2.5 to support older basebands in iOS 5.0.1., as described in the description:
iPhone Dev Team’s iPhone 4, 3G, and 3GS software unlock, now with added PwnApple. Compatible with iPhone 4 baseband 01.59.00 and iPhone 3G/3GS basebands 04.26.08, 05.11.07, 05.12.01, 05.13.04 and 06.15.00! Thanks to @sherif_hashim and @Oranav for contributing baseband crashes.
You can follow instructions here on how to unlock your iPhone with ultrasnow.
redsn0w 0.9.9b9d Download Now Available
The iPhone Dev Team has released a new version of redsn0w to assist iPhone 3GS users with old bootroms and the untethered jailbreak:
Update #17d: iPhone3GS owners in our comments section below noticed a problem with the untethered jailbreak available for the old-bootrom 3GS. We’ve corrected that problem in 0.9.9b9d. If you have an old-bootrom 3GS and have already used last night’s redsn0w on it, you can re-run it again without losing anything. Just use this new version, go to Extras->IPSW and manually select the 5.0.1 IPSW, then go back and Jailbreak it again (but you can uncheck Cydia because it’s already installed).
This is still a tethered jailbreak for all except old-bootrom 3GS users.
Here are the download links:
Earlier today, pod2g demonstrated a video of the upcoming iOS 5.0.1 untethered jailbreak, on an iPhone 4. The release should be coming soon.