UPDATE 11/26/2007

Jeffrey Palermo notes that you can use R# in VS 2008 by turning off a couple of features.

Ilya Ryzhenkov, product manager at JetBrains, gives detailed information on R# support in VS 2008 and talks about R# 4.0.

After installing VS 2008 Team Suite yesterday, I thought I'd try the ReSharper 3.0 for VS 2008 download.  The verdict?  Works great unless you use any C# 3.0 feature.  Here's one example of it blowing up (but not crashing):

I'm using:

• var keyword
• anonymous types
• LINQ

That was a simple LINQ query to count the number of types in the .NET Framework that implement IDisposable and end in the word "Context" (to settle a bet).  Here's another example:

That's an experimental API for pre- and post-conditions (for pseudo-design-by-contract) that uses:

• extension methods
• lambda expressions

From JetBrains' website, they clearly state in the download page:

ReSharper 3.0 for Visual Studio 2008 (Codename "Orcas") only supports C# 2.0 and Visual Basic .NET 8 language features. C# 3.0 will be supported in the next major release of ReSharper.

Now I have a dilemma.  Using Visual Studio without ReSharper is like taking a trip in a horse and buggy instead of a car.  Sure, it'll get you there, but you'll have to deal with a lot of crap along the way.  Until R# v.Next comes out, I'll just have to deal with it.  If you're using VS 2008, don't install R# 3.0 if you plan on using C# 3.0.  Hopefully it'll come out soon, but I haven't seen any roadmaps yet, so I'll just wait.