blacksn0w is live * Now Unlock IPhone 3G, 3GS 3.1.2 and baseband 05.11.07 !!!!!

Blacksn0w is a free unlock for the latest iPhone 3G and 3GS
blackra1n is a super simple jailbreak used to install unlock
new visitors, go to blackra1n.com download and have fun

blackra1n RC3 is also live for both Windows and Mac!!! Clean firmware 3.1.2 and baseband 05.11.07 are recommended.

Updates:
Unlock!!!
Hacktivation
Keep legit activation if activated before running app
15 seconds faster, you'll feel it
Tiger + PPC support

DOWNOAD HERE FOR WINDOWS

DOWNOD HERE FOR MAC

blacksn0w is also available on Cydia, add blackra1n.com as repo
requires firmware >= 3.1 and baseband 05.11.07

It appears some users are having wifi issues. Try a "Reset Network Settings" Also, this just enables custom MobileConfig files. To fully enable tethering, go here on your iPhone and download a MobileConfig file for your carrier. Watch out for carrier fees for tethering.

iClarified has made some nice tutorials:

Windows
Mac

Big Thanks too GEORGE HOTZ