Watch out, parents: There's going to be some Mickey Mouse business with your family cell phone plan. Yesterday Disney (NYSE:DIS) announced it would enter the family phone-plan business with a wireless service on the Sprint (NYSE:FON) network. Disney Mobile will include family-oriented content, safety and communications features, and customized voice mail, phones, and headsets.

Mouse-ear head sets might look cute on your little munchkin, but as more companies target pre-teen customers, you might long for the days when Junior tied up the family land line for hours on end.

More than one-third of cell phone subscribers are on family plans, according to a recent survey from mobile-phone research firm M:Metrics. And guess who's doing a lot of the talking? That's right -- your precious little ones. Another study found that 30% of parents with a teen on their wireless plan report that they often run out of minutes and end up paying extra. (Evidently she's subjecting only you to her silent treatment.)

It's not hard to imagine how the monthly lecture will go once Disney Mobile launches:

M-I-C. See ya in dad's study.

K-E-Y. Why? Because he just got the cell phone bill!

Em oh you ess eee.

Strategic branding aside, the cell phone industry is looking a lot like the credit card industry -- but one that's wooing a younger audience than lenders would dare approach. About one-third of kids ages 11 to 17 have a cell phone of their own. Just last year, NOP World Technology found that nearly 14% of kids ages 10 and 11 had their own phones. Industry watchers predict that by 2007 almost half of teens will be flashing their own mobile digits.

Just like a credit card, a cell phone offers convenience, an emergency line (minutes, not cash, in this case), and the opportunity to get in way over your head. And in both instances, many teens (and their parents) insist that they can't live without one.

What's a parent to do? Set limits.

Easier said than done, we know. But without pre-set limits, that cell phone can quickly turn into a credit card with an antenna.

Prepaid credit cards -- essentially a Visa or MasterCard gift card -- offer the convenience of traditional credit cards, but with strict spending limits set by the cardholder (or the cardholder's parents). Similarly, all the major companies, including Cingular Wireless, Verizon (NYSE:VZ), AT&T (NYSE:T), TracFone, and teen-oriented Virgin Mobile, offer prepaid cell phone plans. Buy a phone and a batch of minutes and start dialing. There's no credit check, contract, and -- if you're older than 13 -- no parental signature necessary. When the minutes run out, customers can buy more via the Web or a prepaid card (with a PIN number on the back), or by calling customer service. Prepaid credit cards and cell phones teach children an important lesson that will serve them well throughout their life -- to work within a budget.

What should a parent do when your kid's card or cell phone runs dry? Ground them.

Just kidding. Give your kid a little leeway those first few months. After all, it takes some folks a lifetime to learn to live within a budget. After that, tell them they'll have to bail themselves out of a pinch. (Welcome to the real world!)

By road-testing these financial products under the watchful eye of a parent, teens can be safely ushered into a world where most service providers bank on their inability to show any restraint.

Dayana Yochim owns none of the companies mentioned in this article.