In the highly unlikely event that you have not seen Rob Caron's blog, here is a excerpt and link to said critical resource. BTW, we are getting an increased number of questions regarding 64-bit support in VS 2005 and I hope this article helps.

Best Regards,

-Ken

http://blogs.msdn.com/robcaron/archive/2005/10/28/486302.aspx

 Team System 64-Bit Support
I’ve received some e-mail asking for clarification on what the story is for Team System 64-bit support in this release. Here’s a summary of my findings:

You can use Visual Studio 2005 to compile your application and specify that it should run on a 64-bit operating system either as a native application or under WOW64; however, Visual Studio 2005 itself (including Team Suite and the role-based editions) is a 32-bit application and when installed on a 64-bit Windows operating system will run under WOW64. Likewise, Team Foundation Build is a 32-bit application and when installed on a 64-bit Windows operating system will run under WOW64. For more information, see Visual Studio Development Environment 64–Bit Support.

Note   WOW64 (Windows on Windows 64) is a compatibility environment provided by the operating system that allows a 32-bit application to run on a Windows 64-bit operating system. For more information, see 64–Bit Windows Part 11: Windows on Windows 64.

As you may know, Team Foundation Server runs on top of several other applications, including Internet Information Services (IIS 6.0), SQL Server 2005 and Windows SharePoint Services 2.0.

Windows Server 2003 SP1 enables WOW64 compatibility for 32–bit Web applications in IIS 6.0. Based on the value of a metabase property, IIS will either start a 32–bit or a 64–bit worker process. In other words, IIS 6.0 can run applications in WOW64 or native 64–bit, but not both. For more information, see Windows Server 2003 SP1 enables WOW64 compatibility for 32-bit Web applications in IIS 6.0.
SQL Server 2005 is available in 32–bit and 64–bit editions across the entire SQL Server 2005 product line, from Express to Enterprise Edition. You can use a 64–bit edition of SQL Server 2005 for Team Foundation Server; however, you must install the 32–bit version of Reporting Services when running Reporting Services on the same computer as Web applications that require WOW64. For more information, see How to: Configure IIS to Run 32-bit Reporting Services in WOW64 Mode.
Service Pack 2 for Windows SharePoint Services 2.0 introduced support for running on 64–bit systems using WOW64, and support for SQL Server 2005. For more information, see Description of Windows SharePoint Services Service Pack 2.
Like Visual Studio 2005, Team Foundation Server is also a 32–bit application and when installed on a Windows 64-bit operating system, it should also run under WOW64. However, due to resource constraints, we are not able to provide full test coverage for this scenario in time for RTM.

What is supported at RTM?

You can install the Team Foundation data tier in a dual-server deployment on a Windows 64-bit operating system that is running a 64-bit edition of SQL Server 2005. Since the Team Foundation data tier is hosted by SQL Server, it will run natively on a Windows 64-bit operating system.
You can install Visual Studio 2005 and Team Foundation Build on a Windows 64-bit operating system; both will run under WOW64.
You must install Team Foundation Server application tier, including Team Foundation Server Proxy, on a 32-bit edition of Windows Server 2003.
posted on Friday, October 28, 2005 10:29 AM by robcaron