The Parallel developer centre on MSDN has a growing number of whitepapers that are really worth delving into. I’d started reading this one ( it’s a big one but worthwhile );

Patterns for Parallel Programming- Understanding and Applying Parallel Patterns with the .NET Framework 4

before I’d realised that it had a whole bunch of attractive-looking friends as well;

Parallel Programming in .NET 4- Coding Guidelines

Debugging Task-Based Parallel Applications in Visual Studio 2010

Using Cancellation Support in .NET Framework 4

Parent-Child Task Relationships in the .NET Framework 4

.NET Matters- Aggregating Exceptions

Performance Characteristics of New Synchronization Primitives in the .NET Framework 4

and then some perhaps more esoteric but, equally important/interesting ones – it’s not often you see the term “false sharing” appear in an MSDN article;

Thread-safe Collections in .NET Framework 4 and Their Performance Characteristics

.NET Matters- False Sharing

but there’s a whole bunch more up at the developer centre so it’s worth popping up there and having a look around.