I don’t know why these libraries where so hard to find, but alas… here they are.  There is a project called RSS.Net offering support for RSS versions: 0.90, 0.91, 0.92, 1.0, and 2.x.  Also, there is a project called Atom.Net that supports Atom 0.3.  They are very useful for reading/writing feeds.  Also, both are open source and have excellent licenses, so if they don’t suite your needs specifically… hack away…