From Jacob Jarick:
namefix.pl is a cross platform batch file renamer, facilitating quick and painless renaming of filenames. It features all the expected batch file renaming functions, id3v1 & id3v2 support, explorer integration for Windows, and much more. It is especially useful for cleaning up files downloaded via p2p networks. Version 4.0 RC3 may include unspecified updates, enhancements, or bug fixes.