No, like immel said, your library can be as big as the hard drive on your computer. Your iPod doesn't necessarily have all the music your library does. You don't have to buy songs to have them on your iPod either (in short, YES, you can add the AT2006 mp3s.)
Go to File -> Add File to Library (Ctrl+O) and find the mp3...if you want to edit the tags after it's been added to your library, right-click on the song and click "Get Info" and go to the Info tags, and that's where you can edit the tags. Good luck! My iPod is my best friend.
