Kite Hill is still active and open to the public. It is at the intersection of Alicia Parkway and Aliso Creek Road.
Kite hill is fine for light floaters, but don't expect to fly anything with real slope performance there.
There is another site just up the road off Highlands called Lilly Chapelle park. It requires a permit and special access. It is behind the gates of a private community.
http://ci.laguna-niguel.ca.us/index.asp?SID=471