I was just in Mammoth this afternoon, and the roads for the most part are clear, with a little ice here and there... chains would be overkill right now... just take it easy and keep a little extra distance between you and the person in front of you and you should be fine...
Driving on ice for the first time can be a little daunting, but just remember braking is where you usually get into trouble... your first instinct is to step on the brakes, but try and avoid braking as much as possible, give yourself extra room, and don't lock up the brakes... if you do, immediately take your foot of the brake and turn into the direction you sliding...
Dave
Edit: as a side note, not to point out the obvious, but I always LMAO when I see someone with a FWD car, and the chains are on the rear....