Originally Posted by squeakr

Including cable cars. That should set you up well.
To buy the pass you can go to the kiosk at Market and Powell, or at one at the Embarcadero BART station.

SF public transit is confusing so I recommend you check out the site listed above. For example BART, whihc will take you from the airport to Powell St/Union Sq, runs within the city but is not part of MUNI.