Here is a list of great sites with many tools for your security needs.
Netbios auditing tool. www.hackingexposed.com
antivirus experts. www.centralcommand.com
intruder alert. www.enterprisesecurity.symantec.com/products
Kane security monitor. www.securitydynamics.com
win nt/2000 rootkit. www.rootkit.com
Security toolbox. http://ntsecurity.nu/toolbox
I hope some of these links will be of some use to you all here at AO. If you dont see what you are looking for I have more links Just tell me what you are looking for and what OS your looking to use it with and Ill see what I can come up with. If you like these links ask JP if he will put them in his link page. Thanks and have fun.