This program lets you browse to a specified directory, and rename any MP3s you want there to match their ID3 tags.

It does error checking for invalid characters in the filenames, duplicate filenames, and MP3s where the entire tag is missing.

You can rename your MP3s in a variety of formats
[Track Number]
[Track Number] - [Song Name]
[Track Number] - [Album Title]
[Track Number] - [Album Title] - [Song Name]
[Song Name]
[Album Title] - [Song Name]
[Track Number] - [Artist]
[Track Number] - [Artist] - [Song Name]
[Artist] - [Song Name]........[Album Title] - [Artist] - [Song Name]