I'll post this here because I had to rename and convert 20'000 files at once and searched the forum and the web for ever till I found a solution.
So if you have to rename many files at once and just want to drag&drop the whole folder into a program and give that program the instruction how to rename'em, I found this to be useful:
NIYoW - Name It Your Way
http://www.snapfiles.com/get/niyow.htmlTried out alotta programs and found this was the best. It has alotta options. But still stays easy to use. It was the only one I had to install though.
And if you have to convert the bit rate of wav files or other file types into wav or whatever on a LARGE number of files, Soundforge is really the only good solution.
The demo version supports everything:
http://www.sonycreativesoftware.com/download/trials/soundforgeHere's the tutorial on how it works:
http://www.sonycreativesoftware.com/video/video.asp?file=training/SoundForge_05_BatchConverter&title=Training+-+Sound+Forge+-+Batch+Converter&VideoPref=