Cross-Country Ski Weather
Visit The Weather Channel for free maps concerning predicted temperatures and current snowfall:

U.S. national snowfall prediction.

U.S. national map of snow quality.

Look at the weather outlook for the East U.S.

Look at the weather outlook for the West U.S.

Enter city or US Zip

Another Good XC Ski Weather Info Spot:
OnTheSnow.com
Has forecasts for individual ski areas in the US and Canada.