I just came across a (somewhat old) review of Tellico that focuses on importing and working with music collections.
Then I discovered Tellico. It was designed for the KDE desktop environment, but so far I have not encountered any problems while using it in Gnome (Linux Mint 5.0, Elyssa). I was finally able to import my windows based data into a new program with relative ease. All I had to do was export the Windows data as a text file and then import it into Tellico. To be fair, there are quite a few other Linux programs that offer the ability to import text files, but their interfaces were not nearly as easy to use or as straightforward.
It's a very step-by-step review of importing a file into Tellico.