iTunes has not killed file sharing using peer-to-peer clients. There are still plenty of people who share music, video, and other files with one another. If you're one of those, you may want to give the free Cabos a try. It's a simple file-sharing program that uses the guts of Gnutella and Limewire with few frills, but it's straightforward to use.
Type in a search term, and Cabos goes out and files that match what you want. For each match, you see a great deal of detail, including the file size, the speed of transfer if you decide to download it, the estimated time it will take to download, the artist name, the album name, and more. Double-click any file to download it; you can then manage your downloads with the built-in file manager.
There are few nice extras here, but some of them are useful. If you use iTunes, for example, you can search for the artist or album that you're currently listening to, which is a nice touch. But there's not much extra beyond that--for example, there's no player built into the program. But for those who want file downloads simple and straight-ahead, Cabos is a solid bet.