Sprint announced today that it is outsourcing the entirety of its wireless e-marketing and sales operations to InPhonic, marking the self-styled mobile virtual network enabler’s (MVNE) largest carrier customer to date.

InPhonic has basically struck a deal with Sprint in which it will produce a “white label” e-commerce site, which will handle all of Sprint’s sales, procurement and activation online, using InPhonic’s e-business back office system. InPhonic will also take over Sprint’s online wireless marketing and advertising and even have some control over handset pricing. In exchange for this degree of control, InPhonic won’t be collecting any service fees. It will simply get a commission off of any new account activated from its site.

InPhonic founder, chairman and CEO David Steinberg said the deal will cut down Sprint’s customer activation costs by as much as 70%. Sprint will still have to pay for its advertising and marketing campaigns, of course, but all of the associated costs of educating customers, closing online sales, credit, actuation and back-end fulfillment will all be stripped from their budgets, Steinberg said. Admittedly the fee InPhonic will charge per activation will be higher than what a carrier would incur when activating a single customer, but Steinberg said InPhonic would be able to land a lot more of customers.

“Sprint’s done an incredible job at building a brand, but all carriers have trouble converting online traffic to sales,” Steinberg said. “Most carriers have trouble taking their interfaces from the [bricks and mortar world] to the Internet. That’s where we come in. Our systems have always been optimized for e-commerce.”

InPhonic has geared most of its efforts so far at MVNOs and companies looking to have private label cell service. The Sprint deal kicks off a new division of the company, which focuses on dealing with the carriers themselves instead of the carriers’ partners, but it will use the same back office system used for its MVNO group. Steinberg said carriers would focus more and more effort on online sales as consumers become savvier about shopping for telecommunications online.