The advertisers at Sunday's SuperBowl may face a tougher race for the touchline than the sportsmen - with Apple and Napster set to go head-to head in the ultimate digital music smackdown.

Apple will advertise its iTunes and Pepsi co-promotion during the game, tempting tune-lovers with free music inside one in every three specially-labelled bottles. 200 million songs will be given away during the promotion, and a slew of silver iPod minis, too.

Napster isn't prepared to sit on the sidelines, watching Apple consolidate its digital music market dominance. The company's booked its own advertising slots during SuperBowl in direct conflict with iTunes.

The new Napster To Go subscription service will be in the spotlight, and the company hopes to convert many iTunes-using, potentially iPod-owning, possibly Mac-switching people to its Redmond-supported subscription to music life.

At issue: the difference between ownership of paid-for and downloaded tracks, and legal subscription-based access to a million songs. Napster hopes music fans just want access to tracks (for £14.95 each month).

And because these songs can be downloaded to certain music players (not iPods), the music service and third-party iPod competitors hope to dent Apple's lead.

In the background, of course, sits Microsoft. That company's software drives the majority of competing non-Apple solutions. And Microsoft - where executives are currently seeing defeat even on their own Redmond campus - is used to dominating the markets it plays in.

The Super Bowl ad will kick off a $30 million, six-month campaign for Napster To Go, based around a mantra encouraging consumers to figure out how much it costs to fill a music player at 79 pence per track.

Alan Cohen, chief marketing officer for Napster told USA Today: "We think the 99-cent-download model will be a thing of the past."