Microsoft Technical Fellow and C# creator Anders Hejlsberg explains the new C# and VB.NET asynchronous programming model, available as Async CTP (linked below) now, which makes async programming much easier for .NET developers.
Stephen Toub goes deep into the design and architecture of the new Async features in C# and VB.NET, which rely heavily on .NET's Task Parallel Library.
Lucian Wischik digs into the new VB functions and iterators being developed for asynchronous development:
Mads Torgersen, C# specification lead, describes the new C# features to improve asynchronous development:
Download: Async CTP