America's youth are using mobile phones for everything from sending e-mails to playing games, and thousands are turning to the Web to transform their phones into high-tech "whoopie cushions."

"After offering various sound effects, it became clear our audience was very young and that a lot of young guys loved ... stuff like bodily functions," said Cindy Lundin Mesaros, a spokeswoman for Faith's Modtones unit, a ring tone provider for Verizon Wireless.