I've been trying to learn more about functional programming in general lately, and there's a lot of good stuff around to read on it. Unfortunately for me, a lot of the content on the web on the topic uses Haskell to explain the concepts, and I find the Haskell syntax to be somewhat intrusive when trying to get a grip on the core concepts. Still, I probably should make a bigger effort in understanding Haskell :-).
By the way, I've also become a great fan of programming.reddit.com; it's been a very valuable source of interesting links, blogs and articles focusing on dynamic and functional programming, among other topics.
Functional Programming on .NET
Now that .NET 3.5 has RTM, some of the constructs in C# 3.0 make it possible to adopt a more functional style of programming on C#. Some of it was possible in C# 2.0, but the anonymous delegate syntax was still a bit too cumbersome. The new lambda syntax makes it a lot nicer, easier to read and easier to code (though because of the static typed nature of the language it can still be a bit cumbersome at times). Eric white has a lot of interesting tutorials on functional programming with C# 3.5 and LINQ on his blog, in case you haven't yet run across them.
Obviously F# is the functional programming on .NET for now, and it has tons of really good stuff, though personally I'm still trying to wrap my head around it.
I think that, overall, there's ton of good things to learn from other programming paradigms that can helpo make you a better developer even if you're writing your code in a language favoring a more traditional approach. It's certainly very valuable to understand and learn different approaches to problem-solving and incorporate them into your arsenal.