In January, we may finally be able to stop speculating about when Apple will end its exclusive deal for AT&T to carry the iPhone in the United States. That’s when Verizon will start carrying the device too, according to “two people familiar with the plans,” who spoke to Bloomberg.

The end of AT&T’s iPhone exclusivity seems inevitable — the device launched with similar carrier exclusivity in countries around the world, and most of those deals are now ended. Still, iPhone owners and potential iPhone owners who are unhappy with AT&T’s mediocre service (especially in iPhone-dense cities like Manhattan and San Francisco) have had their hopes dashed before. There were rumors that Apple chief executive Steve Jobs might announce Verizon support in the US at the Worldwide Developers Conference earlier this month, but that didn’t happen.

I emailed Verizon and, unsurprisingly, the carrier declined to comment. I believe the most recent words from either company on the topic came at the D conference, where a Verizon spokesperson said there were no plans to support the iPhone in the “immediate future,” and where Jobs responded to questions about ending AT&T’s exclusive deal by saying, “That might happen.”

January 2011 might be far enough ahead to put it beyond Verizon’s “immediate future.” Or iPhone fans may have to prepare themselves for yet another disappointment.

Don’t miss MobileBeat 2010, VentureBeat’s conference on the future of mobile. The theme: “The year of the superphone and who will profit.” Now expanded to two days, MobileBeat 2010 will take place on July 12-13 at The Palace Hotel in San Francisco. Early-bird pricing is available until May 31. For complete conference details, or to apply for the MobileBeat Startup Competition, click here.