Unfortunately, I haven't had enough time to play with the web service, though I keep trying to find a way to make it a job task to learn web services. :-)
More information on the National Digital Forecast Database XML Web Service is available at: http://www.nws.noaa.gov/forecasts/xml/.
More information on the Digital Weather Markup Language Specification is available at: http://www.nws.noaa.gov/mdl/XML/Design/MDL_XML_Design.doc.
Happy Wx hacking!
See also: Weather