AT&T may have some serious dead zones in San Francisco, but Sprint’s 4G network is making its way through the city.  Intomobile noticed the 4G availability today, indicating that Sprint is working on the continued spread of the WiMAX network.

It’s an important step for Sprint, as the envied network helps to bring Sprint back into the forefront of wireless service providers.  Launching the android-powered EVO handset with 4G support was a big move for Sprint, making its company and devices much more attractive to consumers.

Sprint has already made moves towards spreading the 4G access around the country, recently launching the WiMAX network in New York City, amongst other places.  With Sprint leveraging Clearwire for swift expansion, its WiMAX support becomes an integral part of the service provider’s plan.

That’s not to say competitors aren’t already working towards their own 4G offerings, Verizon being one.  The company not only plans to extend 4G to its customers, but will also have the iPhone in its broadening array of devices to choose from.  One way Sprint is hoping to attract and retain users of its 4G network is through third party partnerships, such as the one recently forged with Grid Net.

In other network news, MetroPCS is appealing to its niche customer base, finally launching the LTE network today.