A zoomable map of Central America from Google Maps.
A zoomable satellite map of Central America from Google Earth.
A really cool old map of Central America, which includes "Guatemala, Salvador, Honduras, Nicaragua and Costa-Rica." The map was drawn in 1850. It's really interesting to see how the borders have changed.
An area map of Central America from Nations Online, which shows the Central America isthmus, the Caribbean Sea and the north of South America.
A larger map of Central America and the Caribbean, which shows the topography of the region.
Lonely Planet offers an interactive Central America map, where you can zoom in and out to explore specific Central America countries and cities.
A physical and a political Central America map from Geology.com.
A simple, blank Central America map you can fill in for your own purposes.