AT&T and Apple are fielding two more lawsuits regarding the iPhone: a federal suit and a state suit that both accuse the companies of unfair business practices and violations of antitrust, telecommunications and warranty laws. The suits allege that by not letting consumers modify their iPhones so that they work on other networks, the two companies have conspired to maintain a monopoly. The suits also claim that the companies are unlawfully constraining consumer choice by not allowing users to "unlock" their iPhones and intentionally issuing updates that effectively disable unofficial third-party programs. 

For more on the lawsuits:
- read this article from the AP