I write this with lots of reservations. Simply because mp3, short for mpeg
(motion pictures engineers group) is a 'hotbed' of topics one of which includes would-be copyright infringements as claimed by record labels/companies, songwriters, performing rights societies (ASCAP/BMI), music publishers, and industry pros. As we speak, lobbyists from both camps are still at war, and
a lawsuit made by the music industry to stave off it's release have failed. It's now being appealed. I have no problem with all of this...I no longer purchase 'other' people's music since I've been writing my own these days, and it's a sure bet I would have it available for my use anyway.
The performance is GREAT!  although the format conversion is similar as QuickTime...large!

There are lots of players and encoders and audio catalysts available on the net
as freeware, shareware, trials, and for purchase. Xing and WinAmp are just two of the most popular players and encoders. For the novice, it's another way of creating digital duplicates of the original audio file. Hence, the 'madness' going on with Congress and Lobbyists alike. There's even a stand-alone player/encoder much like a Sony WalkMan so rather than 'buy' that Garth Brooks CD...simply find that song on the net...download to your drive...and make a digital copy to take to the beach!

It's unfortunate though that the protocol for mp3 makes it a large but still a managble format to upload/download. Perhaps when all is said and done it'll be better? There is a hightech group that patented a process that will encode/embed a 'digital watermark' yup...like in checks! The encoding process simply inserts a 'code' into the mp3 file whereas, when one downloads such a file...say from a record company for a fee...you are entitled to 'burn' ONE digital copy on an external mp3 player..that's it! Any other copies will result in the digital watermarking code to continue plastering that second unauthorized copy with warnings of infringement during playback. That's not a good thing!

More on this matter as it becomes available!