OpenSIMS ties together the open source tools used for security event management into a common infrastructure. These tools include NMap, Snort, and many others. The best way to experience it is by downloading the liveCD.
Information regarding Project Releases and Project Resources. Note that the information here is a quote from Freecode.com page, and the downloads themselves may not be hosted on OSDN.
This release contains several major bugfixes. It is available in a LiveCD version that provides a full, working openSIMS server that you can just plug in and try.