MP3 Info Extension v3.4 Build 23

Best software that I have found for mp3s' iD3 tagging. This little piece of software integrates into your Windows quite nicely and adds one extra tab page for File Properties selection. With mp3ext you can add easily album infos as id3s to all your mp3s - it can quite nicely retrieve correct infos from filenames, so you don't have to even type anything (works in most cases).
You can also make your own textlists out from your mp3s -- actually the things that you can NOT do with this are easier to list. Great utility that actually is developed very intensively.