As a result of online conversation with Hermit I have begun the endeavor of creating a concept map for VirusWiki.
May Gates have mercy on my soul.
Ahem.
http://seul.org/edu/report81.html List of Open Source mapping tools
http://cmap.coginst.uwf.edu/docs/makingmaps.html Seems to be a good mapping package
http://mak.sourceforge.net/ Another potential mapping package