What are the flying accommodations in Silicon Valley for private pilots?
Moffett Field is still primarily a Federal airfield. They'll take some corporate jets, but not GA, and prior permission is required. All requests go through Planetary Ventures LLC, which owned by Google.

San Jose is a large international airport, but it appears to have no landing fee, though you'll pay a ramp fee unless it's waived. Some AirNav reviews of the FBO give you an idea of what to expect, and you could contact them for further information.

There are a number of GA airports to choose from though. Including:


Reid-Hillview 
Palo Alto
San Carlos


All of these airports have flying clubs and should offer instruction.

Along with others somewhat further away (a few examples include Half Moon Bay to the Northwest, San Martin to the south, Hayward Executive and Oakland International to the east), depending on where exactly you'd like to be.