Geographical Information

General 

E-Podunk - Browse information on cities, communities, counties, and towns; including universities, libraries, museums, and historical sites

Atlases

Maps and Map Databases

50 States - Information on all 50 states!

Google Maps - get directions, find locations, or look at your house!

Houston Traffic Map - This map form Houston Transtar reflects current traffic conditions in Houston, TX.

MapFling - need to send a custom map with those cool little google pins on it?  They have you covered!

Map Collections

Library of Congress - Maps

Perry-Castaneda Map Collection (UT Austin) - Collection of over 250,000 maps (not all are online)

Nautical Charts

NOAA Charts - National Oceanographic and Atmospheric Administration charts (some are free, and some are not)

Sky Charts

Your Sky - look at the sky from any place in the world at any time. Navigate using latitude and longitude or nearby cities.