TagLib# is a FREE and Open Source library for the .NET 2.0 and Mono
frameworks which will let you tag your software with as much or as
little detail as you like without slowing you down. It supports a large
variety of movie and music formats which abstract away the work,
handling all the different cases, so all you have to do is access
file.Tag.Title, file.Tag.Lyrics, or my personal favorite
file.Tag.Pictures.

But don't think all this abstraction is gonna keep you from tagging's
greatest gems. You can still get to a specific tag type's features with
just a few lines of code.

WWW: http://developer.novell.com/wiki/index.php/TagLib_Sharp