This is a cool event that runs concurrently with the big annual Art Basel art show in Miami Beach in early December. (The MSPF is hosted by a gallery in the Wynwood arts district, which is near downtown Miami rather than Miami Beach and is a fun area to visit during Art Basel.)
The street photography festival is a recent event and has been growing by leaps and bounds, perhaps reflecting the renewed popularity of this type of photography and the fact that there are no other events quite like it. There is a lot of great work on display if you are into this kind of thing — check out the 2012 and 2013 finalists galleries for a sample.
Other street-photography links: