Andate a iscrivervi... 
We encourage all interested parties to sign up to participate in the Beta. You will have the opportunity to use our pre-release product and notify us of any bugs you may discover. You may apply for the Beta by going to http://connect.microsoft.com and signing up under “Available Programs”.
Release Schedule: (these are estimated dates)
Beta Release 3/24/2006
RTM 6/1/2006

Fonte: Visual Studio .NET 2003 Service Pack 1 Beta Announcement
A quando quello del 2005?