Zoomatron-NOAA Charts, MapCruncher, and Virtual Earth
Choose a state from the dropdown to the left, and then pick a chart to look at.
These are government-issue navigation charts overlaid on the Virtual Earth (http://local.live.com) map of the United States. You get all the advantages of both - the detailed navigation of the charts and the draggable, zoomable mappiness of the maps. You can make the charts translucent so you can see the map through it.
For fun, check out the Images link for unusual ways to play with the Virtual Earth mapping tools.
Source: Zoomatron Home