A new permit requirement has been added for 2004. For all those who intend on climbing Mt Whitney via a route OTHER than the main trail, but still want to decend/exit via the main trail, you need to reserve a permit to do so. Below is the quote from the Inyo website.
WHAT IS TRAIL CREST? If you are entering from a trail other than the Main Mt. Whitney Trail and intend to exit at Whitney Portal using the Main Mt. Whitney Trail, Trail Crest applies as an exit quota. This is the only trail on the Inyo National Forest with a quota set for exit. Currently, that quota is 25 people per day with 60% reservable and 40% held over for walk-ins. You may reserve this exit space at the time of reservation for your entry trail (up to six months in advance).
Eric J Lee