More or less, yes. Very easy to use.
It operates much like your MetroLink light rail system.

The SFO extension is literally brand-new. After a lot of legal wrangling, they finally got it built and running. The majority of people still drive or bus in..so the system is still underutilized.

http://www.bart.gov/stations/map/systemmap.asp <- This is the overall system map.

Between the BART site and the SFO site [ http://www.flysfo.com/ ], you should be well prepped to use BART to get into downtown. Once you're off BART - say the Montgomery or Embarcadero Station, you should be able to hail a cab to get to your hotel.

[I am assuming you're taking a daytime flight. If you're arriving at SFO at 1 in the morning, you'll have a tough time catching a cab downtown, obviously.]