The conference hotel is the Sir Francis Drake, in Union Square, downtown San Francisco. See accommodation information.
A good map of San Francisco (PDF) you can download and print.
San Francisco International Airport (SFO) - about 19 MI / 31 KM. (SFO is the major airport in the the San Francisco area.)
Oakland International Airport (OAK) - about 20 MI / 32 KM. (OAK is a smaller airport, and served by several budget airlines.)
To get from the airport to the hotel, you can take BART (Bay Area Rapid Transit), the intercity train system. Get off at the Powell Street stop, and either walk a few blocks north on Powell to the hotel or take the Powell Street cable car to Sutter. The hotel is located on the corner of Powell and Sutter.
You can also take a shuttle; one large local shuttle company is SuperShuttle.
Consider traveling to Oakland airport from within North America. Many of the lower-priced airlines use this airport.
We do not advise driving in San Francisco. Parking is expensive, and it's easy to walk or take a bus to local sights. If you are planning to tour the area before or after the conference, rent a car then; otherwise you will spend $50/day just for parking.
For local transit, consider buying a MUNI (SF Municipal Railway) Pass. Another option is the CityPass, which allows 7-day travel on MUNI and admission to several museums and attractions. Both may be purchased online, or at locations in the area. More MUNI info.
Here are some additional sites for San Francisco hotel and visitor information (most have both):