T-Mobile announced today that it’s launched its HSPA+ network — which offers faster speeds than typical 3G networks — in 25 cities across America. HSPA+ is an advanced 3G network that the company is pitting against 4G rival cellular networks from Verizon and Sprint.

T-Mobile’s HSPA+ network was the fastest in several cities compared to other 3G and 4G networks, according to a recent PC Mag speed test. The site saw download speeds of up to 6.6 Mbps when it reviewed T-Mobile’s WebConnect Rocket USB device, which is more than twice as fast as AT&T’s average 3G speeds. The network upgrade should help to make all of its smartphones faster, and the company expects devices that will take full advantage of the faster speeds, T-Mobile’s director of engineering and operations Mark McDiarmid told PC Mag.

The company’s full list of HSPA+ markets includes:

Los Angeles; Dallas; Atlanta; Houston; Seattle; Tampa and Orlando, Fla.; Pittsburgh; Charlotte, Greensboro, and Winston-Salem, N.C.; Oklahoma City and Tulsa, Okla.; New Orleans, La..; Charleston, SC, Bentonville, Ark.; Anderson, S.C.; Fayetteville, N.C.; New York; Philadelphia; Las Vegas; Memphis; Upstate New York; Connecticut; Providence, RI; and the Washington, D.C. suburbs.

By the end of June, T-Mobile plans to cover more than 75 million Americans with the advanced network. Come the end of the year, the company plans to cover 185 million people in over 100 markets.

The company also doesn’t plan to lower its 5 GB data cap like its rival AT&T. It will also continue to use bandwidth throttling for users that go over the data cap, instead of implementing overage charges. The company has seen data usage increase fivefold over the past year, and it’s also implementing network upgrades like adding fiber-optic connections between cell sites and the Internet, according to Jeremy Korst, T-Mobile’s senior director of broadband products and services.

AT&T is also in the process of rolling out HSPA+ to its network to serve as stop-gap solution until its LTE 4G network is ready. The carrier already has its network software upgraded to support the technology, but it has yet to roll out the necessary hardware to make it accessible to users outside of a few test markets.

Don’t miss MobileBeat 2010, VentureBeat’s conference on the future of mobile. The theme: “The year of the superphone and who will profit.” Now expanded to two days, MobileBeat 2010 will take place on July 12-13 at The Palace Hotel in San Francisco. Register now. Tickets are going quickly. For complete conference details, or to apply for the MobileBeat Startup Competition, click here.