The Grantman Mp3 Tagger is a very powerful, yet simple to use, ID3 tag editor. It allows you to easily change song information (title, artist, album, genre, track number, year, lyrics, and comments) and embed album art.
Grantman Mp3 Tagger also includes features that will make tagging songs with correct information easier than ever. A feature called Lookup Tags searches an online music database for information about a song, as well as its album art. If you're just looking for a song's album art, another feature, aptly named Find Album Art, will help you find the right album art, which you can embed directly in the mp3.