Astronaut Photography

The Gateway to Astronaut Photography

http://eol.jsc.nasa.gov/sseop/clickmap/

The Gateway to Astronaut Photography of Earth hosts the best and most complete online collection of astronaut photographs of the Earth from 1961 through the present.

General

NASA Earth Observatory

http://earthobservatory.nasa.gov

Current satellite images with Earth Science description

Earth Lights at Night

http://antwrp.gsfc.nasa.gov/apod/image/0011/earthlights_dmsp_big.jpg

This composite image shows points of light on the Earth at night, illustrating areas of industrial activity.

Space Weather

http://www.spaceweather.com

This magnificent, constantly updated site actually has much more than space weather, though it has that in detail.