T-Mobile has finally launched 4G LTE in seven cities throughout the United States, with fast speeds now live in Baltimore, Houston, Kansas City, Las Vegas, Phoenix, San Jose, and Washington D.C.

The company made the announcement at its big “UnCarrier” event, where it also finally announced availability for the iPhone, a long-missing part of its smartphone lineup. The iPhone 5 will join the fold on Friday, April 12 for $99 down.

T-Mobile has offered HSPA+ as its “4G” offering for quite some time, but it is widely considered to be “3.5G” than “4G” because it is based on 3G technology. LTE is truly a next-generation offering, and Verizon Wireless, AT&T, and Sprint all offer LTE, with Verizon offering it in the most markets throughout the U.S.

T-Mobile said it expects the new 4G LTE network will reach 100 million Americans by the middle of 2013 and 200 million by the end of the year.

Top photo via T-Mobile/YouTube