Software

Open Source Matsim - http://www.matsim.org

SeSAm - http://www.simsesam.de -- Is this open source?

FDS+Evac - http://www.vtt.fi/fdsevac/

Freeware

Nomad (you've got to register first) http://www.citg.tudelft.nl/live/pagina.jsp?id=b20012b3-3051-4bf6-a260-1ab803944eab&lang=en

Model Index
Aseri - http://www.ist-net.de

Exodus - http://www.gre.ac.uk

EVAQ - http://evacmod.net/?q=node/2066

Legion - http://www.legion.com

PedGo - http://www.traffgo.ht

Simulex - http://www.ies4d.com SimWalk - http://www.simwalk.com

Large list of simulation software: http://www.evacmod.net/?q=node/5#