Spoke to Joshua on this same subject today guys. I would not attempt this mountain without crampons, and an ice ax. Learn self arrest and practice, practice, practice! Trust me, you will aprreciate it when you slip. There are many places along trail above Outpost Camp that are exposed. Above Trailcamp you have the famous 99 switchbacks. There are many exposed areas that if you slip (even in the summer) means certain major injuries or death. People have died up there folks and that is no joke. Once above trailcrest, you have the windows to contned with. Exposed, but with a 3-4 ft. trail between the 1000 ft. drop offs. That said, dress appropriately, bring an ice ax, crampons, and know what you are doing. And most importantly, have fun. It is a stark and beautiful place up there. Check the Mt. Whitney message board. It usually has up to the day accounts on trail conditions, weather, road conditions, etc. The road to Whitney Portal can sometimes be open all the way to the trail, sometimes not. If it is blocked, then expect a few more miles and some more elevation gain added to your hike.
Hope this helps. Now go out there and have some fun!!!!!
Oh and my avatar pic? That is Trail Crest at Whitney