Here's a website for Yosemite Valley Campers Coalition:
http://www.yosemitevalleycampers.org/
After the 1997 floods, the Park Service closed the River campgrounds, but promised to replace the sites, and were appropriated money from Congress to do this. Now they are trying to close the North Pines Campground also.
See also this thread under planning:
http://www.yosemite.ca.us/forum/viewtopic.php?t=266