It is especially useful for indexing large collections of CDs, DVDs, etc, containing a very large number of files and folders.
FS-Db is free for personal use. It can be downloaded from here.
Check out the screenshots here.
It is a .NET 2.0 application for Windows. The .NET 2.0 framework is available for download from: http://www.microsoft.com/downloads/
Please send feed-back, questions and bug reports to: fsdborg