We've been seeing an increased demand for info on 64-bit programming. This site has a bunch of links to related 64-bit content (articles, SDK, multimedia)

Intro to Developing Apps for the 64-bit Itanium based version of Windows

Windows Data Alignment on 64-bit IBF, x86, and x86-64

Platform SDK: Introducing 64-bit Windows

Route 64 - Kang Su Gatlin talks about 64-bit

The .NET Show: Getting Ready For Win64

Hope this help!

--Darryl

Updated with additional link: http://msdn.microsoft.com/netframework/programming/64bit/