FLAIR has a highly visual
module on Search. It demonstrates basic search algorithms like Breadth-First,
Depth-First, and A-Star in a navigation problem for going from a source city
to a destination city.
Rich and Knight have a number of Lisp programs
that match the descriptions in their book.
On Search they provide the following programs:
generic-domain.lisp,
which introduces definitions used in all the search programs.