Finally, Apple announced that the iOS 4.3 update for iPhone 4, (GSM version), iPhone 3GS, iPad 2, 1G, and iPod touch 4G, iPad 3G and will be available for download on March 11. The announcement came just after launching second generation iPad 2, earlier today.
When it is out, iPhone unlockers and Jailbreakers must stay away from updating their devices. As Apple have fixed the exploit used in Greenpois0n, Limera1n, redsn0w or PwnageTool, none of these jailbreaking tools will going to work.
We will update you as and when more tidbits from iPhone Dev Team or Chronic Dev team comes-in.