These sites were nominated for the first Webs of Wonder competition: each is worth a look.
H.G. Wells The Time Machine (http://www.sff.net/people/james.van.pelt/wells/teachwells.htm)
Teenfinity (http://www.sff.net/people/james.van.pelt/teenfinity/index.htm)
The Golden Duck Awards (http://www.goldenduck.org/)
SF Spin (http://www.geocities.com/mariannedyson/sfspin.html)
A Wrinkle in Time (http://www.lausd.k12.ca.us/Lincoln_HS/Burleson/wrinkle.htm)
"Hugo Gernsbacks's Forecast" (http://www.twd.net/ird/forecast/index.html)
Book Summaries (http://www.geocities.com/Athens/Agora/4422/summaries.html)
Andy's SF for Education Page (http://communities.msn.com/AndysUsingScienceFictionForEducationPage)
Joan Thomas's Ender's Game Site (http://www.enderwiggin.atfreeweb.com)
The Mars Room (http://www.astro.umd.edu/education/marsroom/)
Cohen's Silicon Monkey (http://www.siliconmonkey.com/alienindex.html)
Brunner's Ender's Game Site (http://www.erols.com/ftsbrun)
Frymann's Dustmuzzle (http://www.dustmuzzle.com/test/index.html)
Thorne's Underbase (http://wow.underbase.org/)
http://www.edu.uleth.ca/~runte/ncfguide/teacher.htm