The last update for Windows AntiSpyware (Beta) was on 12 August 2005. Its version number is 5745.
You can find definition update information at our security portal. Currently signature updates go up on Windows Update and Microsoft Update on Tuesdays and Thursdays. You can download updates through Automatic Updates, the update feature in Windows Defender, or via the manual update links provided at the portal.
Here's some links that may be useful:Microsoft Malware Protection Center - Security Portalhttp://www.microsoft.com/security/portalMicrosoft Knowledge Base Article 923159How to manually download the latest definition updates for Windows Defenderhttp://support.microsoft.com/kb/923159/
Hope this helps,
Edited by Aaron Hulett - MSFT, 13 March 2008 - 02:41 PM.