Mount St. Helens National Volcanic Monument

This is the official site for the national monument created after the May 1980 eruption. Scientists are predicting (as much as possible) a new eruption in the next few days. There's a live volcano cam also available at the site, but this eruption should be a lot less to look at than the last one.
The main site pointed out by The NSDL Scout Report for the Physical Sciences v3 n20 (October 1, 2004).