Sprint’s CEO Dan Hesse says he hopes to keep the company’s data plans unlimited as the company shifts toward faster 4G services through the WiMax technology it’s rolling out in cities across the nation.

AT&T, which offers Apple’s iPhone, is already capping the amount of data users get with a plan, and Verizon has talked about doing the same. The proliferation of smart phones and other wireless-enabled data-heavy devices has made consumers ever-hungrier for data, and carriers say they’re struggling to accommodate the demand.

In a keynote yesterday at EmTech 2010, Hesse noted that when carriers moved to 3G technologies, “the solution was there before the problem”, meaning few consumers used enough data to justify 3G. Today, Hesse says, consumers are waiting for faster networks.

Sprint is certainly encouraging people to think about what they could do with faster speeds. Its 4G network was turned on in selected cities over Labor Day weekend and will continue to expand to additional coverage areas. Its flagship phones for 4G, which can also operate on 3G networks, are the HTC Evo and Samsung Epic, both of which can serve as mobile WiFi hotspots in addition to functioning as smart phones. Hesse noted that users could run five or six devices through hotspots over 4G.

Hesse said consumers strongly prefer to pay a flat fee for wireless services. “Users will pay a premium for simplicity, for predictability, and for peace of mind,” Hesse said. He believes Sprint can continue to provide unlimited data plans “as long as the usage is reasonable.” He noted that the company will closely watch what happens as other carriers shift to metered plans.

One worry, Hesse said, is that heavy users unhappy with metered plans on other carriers might all shift to Sprint, overwhelming its resources. But he said the company would explore ways to handle changing demand for data before shifting to metered plans. For example, he said, because Sprint expected Epic and Evo customers to use more data than those with less-advanced phones, the company charges an extra $10 a month for unlimited plans on those models.