We used Bay Area
Sailing School for 101 a few years ago, and had a good experience. They're in the Watergate Yacht Center.
I have also heard good things about South Coast Sailing, in
Kemah, but have no personal experience. I suppose
Kemah will be closer to the Bay, and Bay Area closer to the lake, depending on where the
training actually occurs (less time in a no-wake zone).
It really comes down to the instructor, though.