AT&T and Verizon Wireless, with an eye on the success of Amazon's Kindle, are dropping hints about entering the electronic book market. The two wireless carriers, speaking on the sidelines of the CTIA Wireless conference in Las Vegas, made no secret of their interest in e-books, though they didn't reveal specific plans. Amazon's Kindle readers use Sprint Nextel to let people wirelessly download books.

Bloomberg reports that AT&T is looking "beyond phones for new sources of revenue."

The Kindle, which lets users download books over Sprint Nextel Corp.’s network, has done a “phenomenal job” and AT&T wants to be part of that market, Glenn Lurie, head of emerging devices at AT&T, said today.

Verizon Wireless is making plans as well, according to AP:

Tony Lewis, who heads an initiative within Verizon Wireless to provide access to non-phone devices, says that five companies have approached Verizon about wireless connections for e-readers.

Lewis wouldn't say what manufacturers Verizon is talking to. But he hints that they are looking at entering parts of the e-book market that the Kindle doesn't focus on, like college textbooks.

Sprint Nextel, for its part, is reportedly looking beyond the Kindle, hoping to power wireless internet for other gadgets, including dashboard computers and GPS devices.

The wireless carriers' growing interest in electronic readers -- and their revenue-generating potential -- is another sign that the segment is maturing.