At a conference yesterday, Sprint Nextel Chairman Gary Forsee offered details on his company’s plan to deploy a nationwide Wi-Max network, for which Forsee projects a total investment of $5 billion over the next three years. Sprint, the third-largest wireless carrier in the U.S., hopes to beat its rivals in becoming the first national wireless firm to deploy a coast-to-coast network of Wi-Max transmitters that would enable subscribers with laptop PCs, cell phones, and other portable devices to obtain broadband Internet connectivity wirelessly and seamlessly. Through its recent partnership agreement with Clearwire, Sprint plans to spend $2.5 billion to reach 100 million customers by the end of next year, with Sprint providing coverage to 70 million users and Clearwire covering 30 million. (Under that pact, Sprint and Clearwire would provide roaming services to each other’s customers as they build out their respective portions of the nationwide network.) Forsee said that, by linking with Clearwire, Sprint expects to reduce spending on the initial phase of network deployment, on which it had originally estimated an outlay of $3 billion. By 2010, Sprint will spend an additional $2.5 billion to expand its Wi-Max service (dubbed “Xohm”) to 125 million customers. Confirming plans for a “soft launch” of the new network in the Chicago and Baltimore-Washington markets by the end of this year, Forsee boasted: “we in fact will have a mobile broadband network at least two years ahead of other providers that will be out there.”