If you like to spend time in California there is a great resource, the book California Camping by Tom Steinstra. It has the information by geographic area with regional maps so you can look and search campgrounds around Yosemite instead of like the Woodalls and similar directories where you need to search by town and bounce for one section to another.
Current information on campground facilities, length of campsites and numbers at a given length, scenic rating which is a big help as you may find 3 campgrounds in an area but 1 is much nicer with better views or may be closer to a stream for fishing, etc.