Microsoft will officially launch its Zune digital media player and music service in the US today.

Retailing at $249.99, the Zune will be available at nearly 30,000 US retailers, making it the most widely available Microsoft product ever.

Available in black, brown and white, the 30GB digital media player will come equipped with wireless functionality for Zune-to-Zune sharing of select music, pictures and home recordings.

It features a 3in LCD video screen that works in portrait or landscape mode to display pictures and videos, and a built-in FM tuner.

The unveiling was heralded by a series of free concerts in public parks and plazas in urban centres across America yesterday.

Speaking at one of these events Microsoft chairman Bill Gates talked up the Zune wireless sharing feature before "surprising the crowd" by giving away his own Zune to a member of the audience.

"We wanted to bring Zune to life with a celebration of live music shared between artists and fans across the country, and really make today all about embracing the social aspect of music," said Bryan Lee, corporate vice president of the Entertainment Business at Microsoft.

"Zune is all about changing the game to make music more social, and at launch we are just scratching the surface of how wireless technology is going to enable social interaction in the future."

Working closely with industry partners, Zune is exploring new models for distributing and promoting music, Lee added. Through managed wireless sharing, Zune allows consumers to promote and sample select tracks, in turn increasing exposure for artists.

Zune logs the music that users have shared, making it easy to purchase their favourite songs the next time they connect their device to their computer.

The hardware will be accompanied by a replacement for Microsoft's MSN Music store dubbed Zune Marketplace.

Staffed by music writers and editorial music programmers, the service will feature music from major and independent labels and music publishers.

These include Artemis/V2 Records, BMG Music Publishing, Digital Music Group Inc, EMI Music, EMI Music Publishing, Independent Online Distribution Alliance, Peermusic.com, Sony BMG Music Entertainment, Sony/ATV Music Publishing, Sub Pop Records, SuperEgo Records, Universal Music Group, Warner Music Group, Warner/Chappell Music and others.

Zune Marketplace is also working with editorial providers XLR8R, The Fader and NME.