(Credit: Josh Miller/CNET)

Sprint today is shouting its unlimited iPhone 4S data plan from the rooftops, hoping to attract Verizon customers who are hopping mad at losing their unlimited data.

Starting today, you can trade in your current non-Sprint iPhone for the carrier's own model, and get at least $100 off when you sign a new two-year contract.

Of course, the limited-time offer also gets you Sprint's promise of capless data access for the device, and that's what Sprint hopes will be the real draw for fed-up Verizon subscribers.

CNET has contacted Verizon for a comment.

Plan rates and conditions change all the time, but throughout the turmoil, carriers typically protect grandfathered plans until the customer voluntarily upgrades to a new phone or rate. Now Verizon is reportedly planning to force a move to tiered pricing plans.

Many have remained skeptical about Sprint's ability to sustain unlimited data plans for data-hungry iPhone users, particularly for the next version of the iPhone, which is sure to include LTE capability at long last.