iTunes is handy for keeping your music collection organized. But the more music--and the more iPods and iPhones--you accumulate, the messier it gets. Enter iLibs ($20, 60-day free trial): This easy-to-use application allows you to create multiple iTunes libraries, which can be synced to multiple iPods and iPhones.
iLibs works separately from iTunes, and the hardest part of using it is remembering to launch it instead of iTunes itself. In iLibs, you can create a variety of iTunes libraries for separate users or different genres of music. Creating a new library is as simple as clicking a button; iLibs does most of the work (including launching and closing iTunes when necessary) for you. You select which songs you'd like to add to the new library, and then iLibs launches it for you.
You also can use iLibs to assign the various libraries that you create to different users. So if you and your kids are sharing one computer to manage all of your tunes, you won't be forced to wade through a collection of Jonas Brothers songs every time you want to create a playlist.
The various libraries that you create can be synced to different iPods and iPhones, which makes it easier to determine which tracks do and don't make it on to your portable device. You can accomplish this manually in iTunes itself, but iLibs's approach is more streamlined.
iLibs's interface is pretty bland, and the application lacks the polish and pizzazz of iTunes itself. But it's easy to use, and if you're sick of unwanted tracks appearing in your iTunes library, iLibs will make your life easier.