Scripts to add replaygain tags to a flac collection

If, like me, you like to be able to play your music without constantly having to lunge for the volume control, and you store the master copy of your (ripped) CD collection in FLAC format you might be interested in a quick way to (re)calculate all the ReplyGain tags on your music. I'll also go into how to automatically create smaller MP3 copies of the files with the replaygain bias "burned in" so stupid players still get the volume right.
Finally, there's another little script here that can be used to fix up issues like inconsistent artist naming. It only does "The X" -> "X, The" at the moment, but it's easy enough to extend.
Read on if you're happy with shell scripting (and a Linux or advanced Mac OS X user).