Alien: Assembly Required http://pbskids.org/arthur/games/alien/ This site is a fun interactive game that lets you watch an introductory video then design your own aliens and see them come to life. You can also print out an image of the alien you created. The game uses a Flash plug-in that is downloadable from the site.
Mars http://www.nineplanets.org/mars.html Was Mars host to alien life? Use this site to learn more about Mars, one of the planets that have been featured in alien stories. The site also has real images from the surface of Mars.