County-level map of the US

Hi R-sig:

I'm just an old guy and new to this list... But have been using R for
years now.

I want to make a map of couties in the US with shaded colors that depend
on the level of variable "Y" that I want to map.

I have the US county and state fips codes and the Y variable.

How do I do this?

Please reply to pzs6 at cdc.gov

Thanks,
Phil Smith
pzs6 at cdc.gov