World's largest map store.
This is a great web site to find anything on the surface of the earth. You can switch between topo, satellite and road, a great way to find mines or cabin in the back country.
USGS maps are available for download for free. This includes the most recent versions and historic versions of maps no longer in print. Once you download the files you can unzip and open them with Adobe. Then you can select which layers of data to show. Pretty slick really and all for free.