The 415 Mission Street building is called the "Salesforce Tower" formerly known as the Transbay Tower. Its build directly on top of the Transbay Terminal.
Art - Advertising, Signs, Billboards and Writing, Buildings - Misc, Events - Construction
After Completion it will be tallest building in San Franciso at 1,070 ft (326 m). The Tower is supposed to be finished in 2016.
Links: www.skyscrapercity.com, virtualglobetrotting.com