The buildings huddle around a central services area called The Commons. It is taking shape now and should be open in April 2009 with a range of food options. Gellos listed Indian, American, Mexican, Asian, deli, coffee and ice cream. The Commons will also have a mini day spa salon, camera store, bank and post office.

There will also be a sports bar, Gellos said in an e-mail, confirming plans for an on-campus watering hole that last year were still tentative.

Some of Microsoft's human resources team has already moved into the former Eddie Bauer headquarters, which is being retrofitted as part of the expansion.

That building will also house a new company visitors center and store, on track for completion in a little over a month. A portion of the store will be open to the public, a change from current practice, but no, the public will not get the Microsoft employee discount. Think hats, mugs, shirts, books.

Part of Microsoft's commitments to ease congestion in the area is a new 520 overpass at Northeast 36th Street connecting the main and west campuses. Gellos said work on that project could commence later this month.

A big driver of the expansion is crowding in the company's existing buildings, exacerbated by continued increase in the company's work force. Total employment at Microsoft globally grew 18 percent in the year ended June 30 to 91,259. Of those, 39,311 work in the greater Puget Sound area.

And the hiring continues: Microsoft added 2,500 employees globally in July and August. In Puget Sound, the full-time staff swelled to 40,580 through the end of August.

For background on the expansion, check out this in-depth story from November 2007.

(Note: I'm out of the office this week. This post was written in advance and scheduled for publication today.)