Music and pictures for your mobile phone. Bloomberg Boot Camp, a report on today's technology. Ringtones and wallpapers are big business….with millions of mostly young people customizing their mobile phones. But the add-ons don't have to cost a lot of money. A Web site called Myxer makes it simple to make ringtones and wallpaper out of songs you already have on your PC. And it also makes other content available from independent artists and advertisers. Founder and CEO Myk Willis says Myxer now has about 7 million users…

"Our consumer facing products target college aged people, 18 to 24. About half of our audience is 18 to 24. Another 25 percent of it is 13 to 18. So it definitely skews young. But you know we have such large numbers that we actually have a larger number of older users using the service than you might expect. Some of the things that we've been able to enable that weren't possible before we came around are niche mobile content. For example, the Center for Biological Diversity has a whole set of endangered species ringtones that they've done. So they have recordings of these endangered species that they make available through their Web site and also mobile downloads. And they use Myxer to deliver that to the phones of their group's members."

Creating an account on Myxer is free. Keep in mind you will have to pay for text messages and the data involved in downloading the content. The site also has ad supported games available for download….depending on carrier restrictions. You can find more information at m-y-x-e-r.com. Bloomberg Boot Camp, I'm Fred Fishkin.