Microsoft Watch has some interesting Longhorn tidbits, starting with this tentative schedule:
- April 2005: Preview/pre-beta release to OEMs and software vendors at the Windows Hardware Engineering Conference.
- Summer 2005 (Microsoft is saying early; we’re hearing July/August): Longhorn Beta 1 released to testers.
- Late 2005 to mid-2006: Interim Longhorn builds (similar to the Community Technology Preview releases that Microsoft’s developer division has been delivering) go to testers
- Some time in the first half of 2006: Beta 2 released
- Q3/Q4 2006: Longhorn released to manufacturing and delivered to PC makers so they can preload it on new machines
- Holiday season 2006: Longhorn hits retail
Well, that’s pretty ambitious, especially given that the story later quotes Allchin as saying, “Beta 1 is only going to be about one-third feature-complete when it hits this summer…” I’ll have to go back through my notes from the XP development cycle and see if there were any similar promises. August 2006 is when it would have to be out to qualify for holiday season shipments, and that’s a pretty ambitious schedule.
Ed Bott 
I’m sure I’m wrong, but I would guess why Longhorn has been long in the making and will not be delivered on this still ambitious timetable is because Microsoft has been taking into account future hardware possibilities and how Microsoft itself sees its own future in say, 2012 and beyond. But as Robert Scoble has noted, small ideas can make for sea changes in computing, e.g., Google and Amazon.