The first Release Candidate of the NUnit Converter has been uploaded to the GotDotNet workspace. It supports the following:
You can download the release here.
In the Release Notes I have detailed the steps required to convert existing code. The document also details differences between the tools that you will need to be aware of before converting from NUnit to Visual Studio 2005 Team System.
I have had a lot of help and feedback on the tool. Thanks to the people who have participated on the workspace. Lastly, I would like to specifically acknowledge Scott Densmore, Peter Provost and Brian Button.