Apple is considering entering the wireless auction that that will be conducted by the FCC in January, according to a BusinessWeek report citing two unnamed sources. The spectrum to be auctioned could provide Apple with the ability to offer its own wireless network service to devices such as the iPhone – which currently depends on AT&T for access. According the article, however, Apple is currently "leaning against participating" in the auction due to profit margin worries:

“With nearly $14 billion in cash, the company can clearly afford the $4.6 billion minimum bid required by the government. […] Rather, the risk for Apple is in entering the generally low-margin, hardscrabble world of running a massive-scale network. […] The company would be on the hook for the massive operational headaches that go with provisioning traffic, activating new subscribers, and fielding their angry calls when service glitches occur.”
Apple becoming a wireless carrier seems quite unlikely, but owning the spectrum may be an attractive plan for Apple, who would no longer need to rely on a phone company. We will have to wait and see. The auction is already the subject of interest for Google, which is expected to make a bid, along with other communications companies.