The release of Microsoft Source Analysis for C# has just been announced - read more at http://blogs.msdn.com/sourceanalysis/. Known internally as StyleCop, the ADO.NET Data Services has been using this for a while, as have other teams I know of.
The tool is great to keep all the code style consistent and follows the Visual Studio default settings, so it's usually the path of least resistance to go with its recommendations. The resulting code text is very clean and after a little time to adjust, it's great to see everyone on the team producing the same style of code.
The way I like to think about it is - when writing or reviewing code, the less attention I need to pay to formatting consistency, the more I can focus on what the code is actually doing.