The MassRenamer application makes it easier to do mass file renaming for a directory. MassRenamer allows replacement (with wildcards), trimming start and end, capitalization, replacing underscores and dashes, and more.
 
It also has an on the fly preview of changes. Currently only does names, although I am looking into support the editing of music tags.

What's New in This Release: [ read full changelog ]

· Fixed small bug with the Replace '-' with ' - ' where it could add an extra space at the end of the file name.