Now that consumers who want an iPhone have two carriers to choose from, people are wondering just what the difference is between the AT&T and Verizon iPhone voice and data plans.

The first thing to remember is that you're not choosing the iPhone for the voice plan. It wouldn't matter, either, because the AT&T and Verizon voice plans are basically identical: $40 for 450 minutes, $60 for 900 minutes and $70 for unlimited minutes.

So let's get to the meat of the argument: data plans. AT&T made the move to tiered data plans last year. That means there's a 2GB data cap for new users. The 2GB plan costs $25 per month, and AT&T also has an option to pay $15 for a paltry 200MB.

Verizon, on the other hand, has a single option: $30 per month for unlimited data.

Here are some things to consider. If you know you consistently use less than 2GB per month (occasional e-mail use with no attachments, maybe a few tweets, light browsing, etc.), then you might as well save $5 with the AT&T plan. But if you use 2GB or more (streaming video and music, heavy browsing), the Verizon plan is worth the money. Even if you only occasionally go over 2GB, the Verizon unlimited data option may still be worth it because AT&T charges $10 per gigabyte over the monthly allowance.