Apple has announced a major prize which will go to the music fan who downloads the 100 millionth song from iTunes in Europe.

The company says: "Music fans in 17 countries around Europe are clicking their way to 100 million downloads on the European iTunes Music Stores. And to celebrate this milestone in the digital music revolution, we are running a special promotion to thank you for helping us make history."

The music fan who purchases the 100 millionth song in Europe will receive a fantastic prize package from Apple, including a 17-inch iMac G5, a 30GB iPod, 10,000 free songs and two tickets to see Robbie Williams.

The Robbie Williams tickets have few valuable extras: two nights hotel accommodation and air fares (or ground transport) to the gig.

Music fans can enter the competition by downloading a song from iTunes or by sending an email.

Apple has published terms and conditions (PDF) for the competition.

The Promotion begins today at 6pm GMT and ends when the 100 millionth song is downloaded.