I have a page that plots the results from a famous election at the county level:
http://www.winwaed.com/products/mapp..._florida.shtml
This is a bit more complicated than what it sounds like you're trying to do. I was try to visually correlate different data.
For what you want, you could create a spread sheet. Put the state in one column and the county names in another. Then put the winners in a third column. Use the MapPoint Data Import Wizard to read the data.
Choose the shaded area map.
Richard