[ http://www.dshield.org/ ]
Distributed Intrusion Detection System firewall system. Provides reports on attack methods.
F-Secure Virus Information Centre
[ http://www.f-secure.com/v-descs/ ]
Provides a database of viruses with descriptions on each one and what they do.
Return on Information Security Investment
[ http://www.adrianmizzi.com/ ]
Site that allows you to assess the Return on Information Security Investment for your company.