Loren Heiny is has begun posting screenshots from his work developing IDE plug-ins allowing inked comments to be made on source code. Personally, I think this is a tremendous use of the Tablet. DevX has just put up my article on literate programming in .NET using Word (in other words, a Word document whose code listings are supported by a “compile this!” smart tag). I was able to use Word's ink annotation capabilities in that project, as well (especially when ink comments are set to “float in front” of the text), but Loren's is definitely the more focused effort.