As we inch closer to the eventual launch of a T-Mobile iPhone in 2013, the company continues to upgrade its network in major markets. Today, it pushes its iPhone-compatible HSPA+ 4G offering to a handful of new metro areas including the following:

• Atlanta (including Roswell, Alpharetta, Marietta, Covington and Conyers)
• Seattle (including Lynwood, Bothell, Mill Creek, Edmonds, Redmond, Kirkland, Woodinville, Bellevue, Issaquah, Sammamish, Kenmore, Mercer Island, North Bend, SeaTac, Burien, Tukwila, Renton and Lake Stevens)
• Minneapolis (including St. Paul and St. Cloud)
• San Francisco Bay Area (including Fairfield, Monterey, Napa, Petaluma, Salinas, Santa Crus, Santa Rosa and Vallejo)

This brings T-Mobile's total number of 4G-supported metropolitan areas up to 18. The company plans to introduce its own LTE network at some point in 2013.