Smithsonian Institution
National Museum of Natural History: Global Volcanism Program: Popocatepetl Mexico
A lot of links to Popocatepetl in Mexico. You can link to background information, graphics and images, items of interest, menu of interest and useful links.
Other
Popocatepetl
Basic information on the volcano Popocatepetl. Also includes brief information on the two eruptions in 1997 and 1998.