Rumours have been swirling for weeks, and next Monday, some of them will become reality. It’s almost a certainty that Apple will be launching some sort of online music service, probably closely linked with its iTunes software (or the bundled MusicMatch that comes with Windows versions of the iPod). My guess (and it’s an informed one) is that Apple will use the AAC format that has been included in Quicktime since last year. AAC is a new compression format that squeezes files smaller than MP3, but will allow some form of digital rights management. The files will still likely be convertible to MP3, allowing Apple to save face with the file-swapping masses, while satisfying the music industry’s need to get paid. As for prices, who knows? But in my opinion, even $1 per track might be a hard sell.