Yes there are. MusicMatch Jukebox is the program that Apple chose to partner with; however, there are a number of other 3rd party applications currently available that offer differing degrees of features. Check out the Software Compendium for a breakdown of each of the offerings.
I'm a passionate, long-time lover of Apple products, and was a civil draftsman and graphic designer before creating the iLounge web site. My prior projects include work for The Los Angeles Times' LATimes.com, and the company Creative Domain, where I developed websites for clients including Columbia Pictures, Disney, Fox Studios, Universal Pictures and Warner Brothers. As the Publisher of iLounge, I direct the site's community forums, photo galleries, iPod User Group, and general business affairs, which have grown under my watch to over sixteen million page views every month. I'm happily married with one daughter, one dog (Rocket the Wonderdog), one cat (Ferris), many iPods, iPhones, iPads, and two turntables.