Hop voilà ce que j´ai trouvé =>
Longhorn Beta 1: Late July
As for Longhorn Beta 1, that milestone release is still on track for " this summer," although Microsoft officially missed the original internal release date of June 30. My sources say that Microsoft now plans to ship Longhorn Beta 1 in late July. The beta 2 release is still scheduled for November. Internally, most Longhorn product groups have already shipped their beta 1 code to the Windows team, and Microsoft is now prepping various 5200-series builds ( post-beta 1) for internal rollout and testing. My sources describe Longhorn Beta 1 as one of the most stable beta 1 OS releases in Microsoft history, although it will lack most of the UI niceties the company plans for future releases. Beta 2, I´m told, is going to be " incredible" and " far more impressive than people now realize." We shall see.
Donc ils sont encore à la bourre, il faudra attendre fin juillet mais ça vaudra le coup car la beta 1 sera stable.