  I am also a co-developer/perpetrator of PDB, a graphical debugger for the UCPOP family of planners(I'm not just a programmer...I'm also a client). The number of people whose lives it has touched grows each and every day. The manual is <a href="http://www.cs.washington.edu/research/projects/ai/www/pdb/pdb.html">here</a>. <p>
