Renaming the occasional file is a simple enough process, but it can quickly become laborious if there are a large number to work through. This is where batch renaming tools come in. Here's four of the best, which are free too.
Advanced Renamer 3.03
Advanced Renamer, as the name would suggest, simplifies the process of renaming a large number of files by making it possible to process them as a batch. Files can be simply dragged and dropped into the program and you can then use 'methods' to choose renaming criteria.
TheRenamer is a simple tool for renaming TV or movie files, so cryptic file names like [vd-mux-ita]The.Unit.1x01.Piromane.ITA.DVDMux.[colombo-bt.org].avi will quickly be replaced with a rather more sensible alternatives, such as The Unit.1x01.First Responders.avi.
Panda Batch File Renamer 1.6
At its simplest, Panda Batch File Renamer 1.6, lets you change the case of a file name, replace some text with another, or remove particular text altogether. The program can also insert new text, though, and this can be extracted from metadata within the file itself. So you could create a set of rules that, say, renamed your MP3 files to include the track, album and artist (and genre, track number or year), while photos can be renamed to include their subject and dimensions.
Rename Master 2.9.4
Rename Master is beautifully formed, free and portable application enables you to rename large groups of files with ease. It also allows you to change the tags found in MP3 and JPEG files too, so if you've accidentally misspelled an important tag in 100 files, you can now change it with the minimum of fuss.