I little while ago I wrote about the lack of resharper plugins and sample code for the plugins [http://www.kinlan.co.uk/2006/11/resharper-20-plugins.html]. Jetbrains has now started up a new page [http://www.jetbrains.net/confluence/display/ReSharper/ReSharper+Plugin+Development] which contains guides and also sample code on how to create plugins. You will need Resharper 2.5+, but that is a free upgrade if you already have resharper.
