Killer lake Nyos in Africa http://perso.wanadoo.fr/mhalb/nyos/nyos.htm
Carbon dioxide gas outbursts from lakes Nyos and Monoun in Cameroon, West Africa, killed hundreds of people. A controlled degassing operation is scheduled to begin in January, 2001, for reducing the risk of future carbon dioxide suffocation from these killer lakes.
The Electronic Volcano http://www.dartmouth.edu/~volcano/
A pioneer site started by Professor Dick Stoiber at Dartmouth College providing information on active volcanoes. Not well updated since 1997, but older information is excellent.