I wrote a series of posts as a climber’s guide to camping in Joshua Tree National Park.
You can see them here.
Part 1: http://www.rockgrrl.com/blog/2009/11/climbers-guide-to-joshua-tree-camping-part-1/
Part 2: http://www.rockgrrl.com/blog/2009/11/climber%e2%80%99s-guide-to-joshua-tree-camping-part-2/