Say Cheese! A picture is worth a thousand words to cell phone carriers.

Following Japanese companies, U.S. wireless carriers have begun letting users transfer photos over their 2.5G and 3G networks. AT&T, Cingular and Sprint PCS now offer clip-on phone cameras that may be a boon for businesses, says Yankee Group analyst Sarah Kim.

Cingular users can get a Sony Ericsson T68m with the clip-on CommuniCam MCA10 for $167. AT&T's camera-compatible phones range from $79 to $199, and users pay about $12 monthly for 2MB worth of transfers over AT&T's mMode service. If you won't need to make that many transfers, you can get basic service for as low as $2.99 a month.

Transfers average 40Kbps to 60Kbps on 2.5G networks. But Sprint PCS offers businesses a pricier 3G digital-imaging service with speeds of 50Kbps to 70Kbps, which requires a subscription to www.activephoto.comto view your image files.