Microsoft announced official Xbox 360 sales numbers along with their quarterly earnings announcement. As expected the Xbox 360 sales numbers are below Microsoft's original sales goal.

Microsoft sold 1.5 million units in 2005. Main reason for the low number has been manufacturing issues. Microsoft says now that they will sell 2.5 million Xbox 360 consoles until end of February, 500,000 less than predicted in the original 90 day goal.

In the USA MS sold 900,000 units. Europeans picked up 500,000 Xbox 360 consoles and Japanese gamers only bought about 100,000 units.
Microsoft is confident though to overcome production issues and sell between 4.5 to 5.5 million Xbox 360 by end of June.
We will see. At the E3 2006 in May I expect Sony to turn on the heat for the Sony PS3. They might launch it in Japan right after the show and for the Holiday season in the US and Europe.
More details in this Reuters story and in the Microsoft Earnings release.

Wal-mart and Amazon have on and off availability of Xbox 360 bundles. To find a unbundled Xbox 360 premiums system try this Xbox 360 Desktop Tracker tool.