htc evo 4gHolding true to its promise, Sprint lit up New York’s first 4G cellular network today, in addition to other cities like Hartford, New Haven, and Trenton.

The news brings the total number of cities with Sprint’s 4G network, which uses WiMax technology, to 61. The company also lit up 4G in New Brunswick and Tampa today. Sprint says it’s still on track to bring 4G to other major metropolitan areas like Los Angeles, San Francisco, Miami, Denver and Washington DC by the end of the year.

Sprint’s 4G operation merged with the wireless ISP Clearwire’s in 2008, which means that both companies lay claim to the 4G network currently being rolled out. Time Warner, one of Clearwire’s investors, is also offering 4G internet services using the network.

Now New York-based users of Sprint’s Evo 4G and Epic 4G Android smartphones will finally be able to take advantage of their device’s next-generation wireless speeds. One recommendation to Sprint users: Keep 4G off until you actually need the extra speed, since the technology is a severe drain on battery life.

Sprint has had a major head start on deploying its 4G network, but its competitors aren’t just sitting on their hands. Verizon plans to have its LTE-based 4G service live in 2011 — whereas AT&T is taking a longer approach by pushing its 3.5G HSPA+ service (which is faster than 3G, but slower than 4G) in 2011 and deploying 4G in 2012. T-Mobile has been rolling out its HSPA+ service throughout the year, and is currently billing it as 4G.