you can download it at http://www.apple.com/itunes/download/.
It is a free universal program that was built for macs but can run on PCs as well, and is generally considered the best free music managing software. It does basically everything, and is pretty intuitive. If you can’t figure it out after you download it, let me know and I can help you through it.
AmaroK is praised a lot. Though I take it you’re not using a Linux distribution, so you’ve probably never heard of it. However, once version 2 arrives, it’s supposed to have a Windows version too, so you might like it.