This time the regulatory authorities have nabbed a big fish in the quest to clean up the ringtones and mobile content subscription business: AT&T (NYSE: T) Mobility. The company has been fined by the Florida Attorney General’s CyberFraud Task Force, and is paying $2.5 million to the AG’s office in addition to refunding customers for supposedly “free” ringtones and other mobile content sold by third party providers, reports ClickZ. AT&T also must pay an additional $500K to be used to educate consumers about safe mobile use. Also, the refunds to customers could be anywhere from $10 million to $45 million, depending on the number of customers who claim they were wrongly billed, reports Tampa Tribune.

These “free” services are what we have been covering from the start: fine print shows they aren’t, and are usually operated by third party aggregators. Under the settlement, AT&T Mobility agreed to police third-party advertisers to make sure consumers are no longer misled. The company also agreed to make billing more transparent.

The task force also is launching investigations of Verizon (NYSE: VZ), Sprint/Nextel, Alltel (NYSE: AT) and T-Mobile…and then smaller carriers could be next. Italian mobile content provider Buongiorno (BIT: BNG) is also being sued by Florida AG, though the company has been defending itself.