The City and County of San Francisco has a new open data site:
Please follow the link to the site to search, browse and view San Francisco data.

Description: Street Use and Excavation Permits

Agency Name: Department of Public Works - Bureau of Street Use and Mapping
Time Period: Live data
Frequency: on demand
Location of dataset:
Format: web
Location of Data Dictionary: N/A
Additional Details: Query by street name only

DataSF is a clearinghouse of datasets available from the City & County of San Francisco. Our goal in releasing this site is:
(1) improve access to data
(2) help our community create innovative apps
(3) understand what datasets you'd like to see
(4) get feedback on the quality of our datasets.