As the number of teens with cell phones continues to rise dramatically, so do the bills that Mom and Dad have to pay, since the accounts are in their names. Parents are concerned not just over the cost of passing out mobile phones to all the kids, but there’s also concern over who their offspring might be talking to.

Sprint and Sanyo have teamed up to offer a phone and service that allows parental control over whom their kids can call and who calls them. They simply enter all the ‘allowed’ numbers in the phone’s contact list and then lock out any changes. Only those numbers on the list can call in or be called. Advanced features that cost extra money, like online services and ringtones can also be controlled.

The Sanyo SCP-2400 phone (pictured above) comes with teen-friendly features and is available in five different colors.