Offered initially will be 435 commercial-free radio channels in genres ranging from rock to jazz to "One Hit Wonders." In taking aim at the growing popularity of satellite radio providers Sirius and XM Radio, the service will let you download the channels on the computer and transfer them to your phone or mobile device to play back later.

With Bluetooth wireless technology, the content can move from the phone, through the car stereo, or across the home stereo system . Unlike other radio services, iRadio's technology frees the service from bandwidth limitations, the company said, so that the selection of channels is almost unlimited.

Process of Discovery

"This is all about content discovery, which along with acquisition is a critical component of delivering music on mobile devices," said company spokesperson Paul Alfieri. "Carriers need both to offer music to their customers, and instead of telling them to go somewhere else to search for the content before buying it, iRadio introduces them to a broad array of music and lets customers purchase it on the device."

System requirements include an iRadio-enabled mobile phone, a broadband Internet connection, a PC running Windows XP, and a USB port on the computer. Phones that can handle the service, including the next-generation Rokr E2, are expected in the coming months. Alfieri said the service would not be limited to Motorola handhelds.

Subscribers can expect to pay $6 to $10 for iRadio, depending upon rates established by carriers, which Alfieri said is an attractive alternative to satellite radio services.

Backing Off from iTunes

You will be able to hear a song on the car stereo, for example, and press a key to purchase and download the track over the air. Motorola has collected hundreds of channels of content through agreements with major labels and other producers, said Alfieri, so that operators can customize iRadio's content to complement their existing music offerings.

"Motorola is backing off from its iTunes relationship, and it will be interesting to see how it markets this new offering given that it competes with existing music services offered by Sprint, Verizon, and other carriers," said Yankee Group analyst Nitin Gupta.

Gupta suggested that iRadio might be more cost effective because bandwidth is much less expensive on the PC than it is on the wireless carriers' networks. "But there is a lot of competition from satellite radio and iTunes when it comes to providing audio on the move," said Gupta.

Motorola can grab a chunk of that market because it is among the top phone manufacturers worldwide, the analyst noted. "This is a service targeted at a device that millions of people are buying, and the mobile phone is a good vector for audio, but manufacturers and carriers still have to convince consumers that the phones are not just communications devices," said Gupta.