Analysts at IDC are predicting that over the air (aka cell and wi-fi) downloads will surpass traditional downloads by 2010. Their survey shows the OTA market reaching $1 billion dollars and 50

million users just 4 years from now.
"OTA mobile music storefronts are emerging as one of the most important new channels for fans to discover, purchase, and enjoy full-track music and related content. Key drivers for future growth include music-enabled handset penetration, deployment of broadband wireless networks, increased marketing efforts, bundling and cross-promotion of various music-related services, and driving flat-rate pricing schemes. IDC expects that OTA tracks at about $2.00 each will emerge as a sustainable price point as long as mobile storefronts are well-designed and offer a wide selection of music, and the music listening experience on the device is comparable to MP3 players," says Lewis Ward, research manager, Wireless and Mobile Communications: Entertainment at IDC.
Source: IDC