When you are ripping CDs with Windows Media Player, the player can automatically go out to the Internet to  retrieve the metadata describing the CD such as the album name, artist, track information, etc.  If you are an artist that would like to have your CD or DVD information added to the database, you need to contact All Music Guide (AMG).  Microsoft has no direct control over this listing since we license the database from AMG.  The page http://allmusic.com/cg/amg.dll?p=amg&sql=32:amg/info_pages/a_product_submissions.html describes what you need to do.  Once AMG's database is updated, the data will be propagated to Microsoft and other licensees of AMG’s database.  This usually takes a few weeks.