Correction 11:56 a.m. PST: We messed up. The 9 to 5 Mac blog we cited below is in fact from September 2008, so it turns out this is an old rumor. Because it showed up in our RSS feed Saturday, we, like a number of other publications, took it as a recent post and went from there. Apologies for the confusion.
There have been rumors buzzing around the Internet for some time Apple is secretly preparing a CDMA version of the iPhone, probably headed to Verizon Wireless, and probably by the end of this year. It's no secret Apple has been advertising jobs that require experience in the CDMA wireless standard, which Verizon Wireless and Sprint both use, and is the competing standard to GSM, which AT&T and T-Mobile use, as well as the standard the current iPhone uses.
What's unknown are the exact terms of Apple's deal with AT&T. Neither company will confirm rumors that AT&T's exclusivity ends this year or other rumors that the original deal has been extended to sometime in 2010.
The Web site 9 to 5 Mac offers a few compelling reasons why a non-AT&T iPhone in the near future might be likely, including Apple COO Tim Cook mentioning that the iPhone maker wasn't "married to the one carrier/country model."
In addition, it's known that Verizon was the original preferred carrier for Apple but wouldn't give up the control AT&T eventually did to Steve Jobs.
With Sprint having exclusive rights to the Palm Pre for the year, and T-Mobile's commitment to the G1 and Android, it would make sense that Verizon would push for the iPhone, including giving up distribution to Apple, as AT&T did.
This would give Apple a much larger user base than it currently has, as many people are tied to carriers other than AT&T due to contract restrictions. Eventually it's likely that every major carrier will have the iPhone.