The US ringtone market is worth an estimated $750m in 2009, down from a peak of $880m in 2007

"The music ringtone market is within the decline stage of its short life cycle, according to industry research firm IBISWorld. The company forecasts industry revenue to decline for the second consecutive year - down 15 percent from its $880 million peak in 2007 - totalling just $750 million in 2009.
“Music ringtones practically boomed overnight, but with two consecutive years of decline it seems the industry is exiting just as rapidly as it entered,” said Toon van Beeck, senior analyst with IBISWorld. “And with the ringtone market already reaching its decline stage, its life cycle is only expected to last about 15 years.”"
Source: IBISWorld press release, 21st September 2009