Planning on being in Phoenix early Jan. Thinking about driving to Grand Canyon for couple days but concerned about temperature and snow. Any advice?

Bring blankets, shovels, coats and a good SUV.

The December 2002 issue of "Sunset" magazine has an article on winter in the Grand Canyon (specifically, the south rim).
It looks cold but beautiful! Even the mules are still running.

Winter in the Canyon (South Rim only is open) is cold, but snow is rarely a problem. Worst scenario is what happened to me -- high humidity caused so much fog from the heat within the Canyon that I could barely see anything from the Rim.

If you'll be spending a couple days at the Canyon, make certain you have lodging reservations -- you do NOT want to spend half a day trying to find a place to stay.

The South Rim can be gorgeous in January, even with snow. The Rim Trail will be open (along the edge) so you'll have no lack of vistas. If you plan to stay inside the park, make your hotel reservation now. The nps.gov website has good info on the park. Also, it will cost you $20 per vehicle to get inside the park.

Enjoy!