There are programs at De Anza College and probably other local colleges that certify American Red Cross Swimming Instructors (that's where I got mine) and these teachers are the ones who usually go to work for YMCA or AVAC

But you can hire one yourself if you can just get at them before they find a job with such a place; negotiating a rate between yourselves (higher than what the teachers would receive from YMCA and lower for you than what you'd pay).

That way it'll end up being cheaper for you, and your kids can get individual attention. You will, however, need to have access to a pool (i.e. you have one in your home, or know someone who does)

The teacher at De Anza college is Rich Schroeder who's run this Swimming Teacher's Class
Phone: 408.864.8402
email: schroederrich@deanza.edu