I made it to the top in Jan of 2002. The Mtrs Route is the way to go. The traverse from Trail Crest to the top can be very exposed depending on the amount of snow you encounter. Remember, there is no trail... There are some pictures of the traverse on this site:
http://members12.clubphoto.com/robert634908/943486/guest.phtmltitled: 1997-02-21 On the back side
Remember, Whitney in the winter is not for newbies... I've been up there with 60mph+ gusts and temperatures below 0 (not including windchill).
The hike usually starts between 6000 and 7500 feet depending on conditions...
Winter is my favorite time of the year...