I've just posted a new article on The Code Project about normal map compression, as I mentioned I would do a few days ago.
Click here to read the article and find out why compressing normal maps is so important and tricky.
If you just want to download the NormalMapInstaller, click here (or on the big picture).
For the sourcecode, click here.
If you have trouble starting NormalMapCompressor even with DirectX 9 installed and you are getting a "Microsoft.DirectX.dll not found" error, you have most likely no Managed DirectX installed (or for some reason your managed DirectX doesn't want to start with NormalMapCompressor). To download the latest DirectX version visit Microsofts DirectX site. You might have to install DirectX with "dxsetup.exe /InstallManagedDX" (sorry can't include that 32 Mb file into the installer). Sorry about the inconvenience, on some computers it works instantly, on others there are only problems.
Other than that I'm pretty tired right now and need to sleep, I hope you find NormalMapCompressor useful. For any problems installing please read the article.
Info 2005-07-14: 2 Updates (v1.1 and v1.2) have already happend, just download the program again. New features include better generated mipmaps, fixed errors with DXT5Switched saving and few small new features (like flipping color channels).