As long as AT&T (T) was Apple’s (AAPL) only U.S. carrier, nobody who really wanted an iPhone did much comparison shopping on voice and data rates. You signed up for the AT&T plan that made sense for you and your family, and that was that.

But now that Verizon (VZ) has the iPhone, many Americans will be taking a closer look at how the rate plans stack up. To help them choose, the cost-saving service BillShrink has produced a handy chart — copied in full below the fold — of the various plans offered by the four major U.S. carriers.

Sprint (S) and T-Mobile (DT), of course, don’t sell iPhones — yet. But they do sell a lot of Google (GOOG) Android phones, and that, I’m told, is almost as good.

Below: The full BillShrink chart. If you visit their site and take their survey, you might win an iPad.

Also on Fortune.com:

• Verizon iPhone: The reviews are in
• Will Murdoch’s Daily ever break even?
• Apple is still sucking most of the profit out of the cell phone business

[Follow Philip Elmer-DeWitt on Twitter @philiped]