Lewis and Clark Resources
Link to Mrs. Deacon's Lewis and Clark Project Web page

PBS Online:  Lewis and Clark, The Journey of the Corps of Discovery
Companion Website to the Ken Burns Documentary.
Very extensive site with loads of information and fun stuff too.
Includes biographies of everyone involved in the expedition and an  interactive story in which you lead the expedition.
Discovering Lewis and Clark
Another very extensive site.  Loaded with information on all aspects of the expedition. 
The journey itself is split into nineteen hyperlinked pages indexed here.
 
Lewis and Clark's Historic Trail   This site includes maps with links  describing what you can see along the trail today.