Yes, although not very much in recent history. Several San Franciscans have claims of flurries for very brief times which didn't accumulate, but most of those aren't "counted" in official weather sources because they were too brief or maybe only appeared in isolated areas and weren't observed.
This winter (December of 2009) there was actually some snow in the Bay Area at Mount Diablo State Park:  but that wasn't San Francisco, proper... so it doesn't count!
If we look back into further history we actually see accumulation of as much as 3.5" of snow on New Years Eve in 1882 and 3.7" on February 5th of 1887. There has been recorded accumulation as recent as the inch received on February 5th in 1976 (historical source:  - corroborating source for more recent 1976 stats:  )
To address the "what was it like?" portion of the question, here is a great picture (with people) from the 1882 snowstorm: http://SanFrancisco.wikia.com/wiki/File:1882sfsnow.jpg and a less personal one from the larger 1887 snowstorm: http://SanFrancisco.wikia.com/wiki/File:1887sfsnow.jpg
A long account of the snowstorms (which contains even more detail than this already lengthy answer) can be found here:  if you're into that sorta thing.