Add this to Cingular Wireless' increasingly odd customer service record -- Reuters reports that the wireless carrier will be charging customers with older phones an extra $4.99 monthly fee on top of their current service plans.

Huh?

The idea, according to the company, is to persuade customers to stop using TDMA and move towards GSM, allowing Cingular to maintain a single network technology.

"Cingular, which hopes to create savings by converging to a single network, said last month on a conference call that it would risk an increase in customer cancellations for the rest of the year as it works to eliminate the older technology," the article states.

But this isn't just about a few customers: Cingular said the fee would apply to about 4.7 million subscribers.

"Some customers will qualify for discounts on their new phones," says spokeswoman Rochelle Cohen. But others won't -- and many will have to upgrade their plans in order to do so.