On February 22, 2010, federal law governing possession of weapons in national parks will change. Individuals not otherwise prohibited by law from possessing a firearm in compliance with California state law and Federal law are permitted to possess a weapon within Yosemite National Park.
Federal and state regulations restrict the possession of firearms in federal buildings and school zones.
If it is going to be allowed in my favorite national park, then I am assuming it will be allowed in all. If you allowed by state law to carry, then you will be allowed to carry in the national park in that state. I hope this clears it up.