National Weather Associasion Job Board
American Meteorological Society Career Center
The Weather Prediction - Jobs in Meteorology
-- Good overview web site that talks about advantages and disadvantages to working for the NWS, TV-Radio stations, military, private consulting, etc. Also includes great links to further web sites in these areas.
Penn State University Weather Job Board
-- Includes links not only to US jobs, but also internships, Co-Op opportunities, graduate assistantships, etc.