Mobile payments startup Zong, which is one of our DemoPit exhibitors at TechCrunch50, thinks it has the answer to micro-payments on the Web for social apps like gaming, dating and classifieds. It uses your mobile phone as a way to pay for things such as virtual goods in Facebook apps.

The way it works is that you enter your mobile phone number to pay for something on the Web, maybe a virtual cowboy hat for 5 cents. Then you get a test message on your phone with a pin number. If you enter that pin number in a widget on the Web, the charge will be reflected in your cell phone bill.

Using mobile phones to bypas the issues that micro-payments still have on the Web is a smart move. Nobody wants to use a credit card for small purchases of a few penies or dimes, because the finance charges are too high. Whether anyone wants to pay even a few pennies for a Facebook app is a whole different matter.