Hello Andre,
As per you and Zeo, here is a possible timeline:
1/2005
2/2005
3/2005 - XP 64 / Longhorn Alpha : Milestone 9
4/2005
5/2005 - Yukon / Visual Studio 2005
6/2005 - Longhorn Beta 1
7/2005
8/2005
9/2005 - PDC 2005 / Longhorn Beta 1.1
10/2005
11/2005
12/2005
1/2006 - Longhorn Beta 2
2/2006
3/2006
4/2006 - Longhorn RC1
5/2006
6/2006 - Windows Mobile 2006
7/2006 - Longhorn RC2
8/2006
9/2006
10/2006 - Longhorn RTM
11/2006 - Longhorn GA
12/2006 - XBox2
