An Alpha version of code complexity addin for Visual Studio 2010 is available. The extension can be found at project page at CodePlex.
The extension shows the complexity of the methods in the IDE near the method and measures the method “health”.
For example, view of healthy methods (low complexity):

And example of too complex method:

Currently, the complexity metric shown is simple complexity (defined by Code Complete). This metric counts the number of possible paths in the method. A healthy method is one with low complexity; a method with 10 paths is not so good and is worth simplifying.

Keep it green!