Q1 2008 on VZW; Q2 2008 on Sprint. If you want further details, they are not concrete nor should you think of them being reliable (heck, the above ones are only estimates/plans by the carriers). The release code should be OS 4.3.1, as it's being tested on them now. That better?
In the beginning the Universe was created. This has made a lot of people very angry and is widely regarded as a bad move.