Napster says it may have found a significant advantage in its fight against Apple's iTunes: mobile phones.

Apple's iTunes music service sells digital music that's playable only on the iPod and comes with DRM, or digital rights management, whereas Napster's can be played on various MP3 players and some mobile phones, Reuters reports. Moreover, Napster expects that other compatible devices will be released in the future.

However, Apple will release its iPhone later this year, giving users the ability to play their iTunes library on the device. Also, Apple has attempted to press the music industry for the removal of DRM from songs sold via iTunes - to make iTunes music more accessible and to increase sales.

Accordingly, whatever advantage Napster can gain from selling music playable on compatible mobile phones will have to be gained quickly.