It seems pretty clear that the nation's wireless carriers are less than thrilled about Google's entry into the telecom world. In case you still had any lingering doubts about the animosity, however, AT&T has taken the relationship to the next level by filing a complaint against the service with the Federal Communications Commission.

According to the carrier's complaint, Google has been restricting calls in places where service providers charge higher fees. "By blocking these calls, Google is able to reduce its access expenses," the company wrote in its letter. AT&T is basing its complaints on new reports about Google Voice.