With the popular Apple iPhone 4 set to arrive on the Verizon Wireless network in a couple of weeks, the results of a recent ChangeWave survey have indicated that nearly 16 percent of the AT&T customers intend switching carriers in favor of Verizon.

In addition, the survey also revealed that while around 41 percent of the respondents are still undecided about whether to continue with AT&T or move to Verizon; almost 15 percent of the T-Mobile customers are also likely to switch to Verizon when the carrier starts selling the iPhone.

The percentage of smartphone users planning to move to Verizon from other carriers, once the CDMA version of the iPhone is launched, is essentially a reflection of an unknown share of answers based a motivation of social desirability. Nonetheless, the 16 percent figure for AT&T indicates that nearly 15 million customers are contemplating a switch to Verizon.

If the statistics shared by the ChangeWave survey are accurate, a chunk of the approximately 25 million new users at Verizon – estimated by the analysts at RW Baird – will actually comprise those switching from AT&T.

Interestingly, with AT&T having revealed that a whopping 90 percent of its existing iPhone users are within a 2-year contract and some will hence have to spend as much as $325 as termination fee, the switch over to Verizon may not be an easy decision for most AT&T customers. However, Verizon’s trade-in program may apparently soften the financial blow.