This whole online MP3 download service business is getting nasty. The Register reports that MusicMatch and Apple, once in cahoots, are now doing what they can to elbow the other off the stage. “Apple and MusicMatch are locked in a battle to see who can infect as many personal computers with DRM (digital rights management) as quickly as possible,” The Register says. Good point: with different systems in place for managing the MP3s you download, users will find it hard to have two or more subscriptions to these services going at the same time. The upshot: whichever software you use will determine which subscription service you use.