Anti-Virus:
ClamAV http://www.clamav.net/
KlamAV (Frontend for ClamAV with wizard configuration utility) http://klamav.sourceforge.net/klamav....php/Main_Page
AVG Anti-Virus http://www.grisoft.com/us/us_index.php
Kaspersky Labs http://www.kaspersky.com/
McAfee http://www.mcafeesecurity.com/us/pro...s/category.htm
Symantec http://www.symantec.com/product/
Vexira http://www.centralcommand.com/
F-Prot http://www.f-prot.com/
Sophos http://www.sophos.com/
Bit Defender http://www.bitdefender.com/
AntiVir http://www.antivir.de/en/index.html
Open Anti-Virus Project http://www.openantivirus.org/
Avast http://www.avast.com/index.html

Alternative browsers for Linux distributions:
Firefox, Thunderbird and Sea Monkey http://www.mozilla.org/
Konqueror http://www.konqueror.org/
Opera http://www.opera.com/
Epiphany http://www.gnome.org/projects/epiphany/

Linux firewalls:
Most popular Linux distributions use some form of integrated gui firewall tool to ease security setup such as SUSE Linux, RHEL and Mandriva Linux. For those distributions that rely on the end user manually configuring their IP Tables to secure their OS there are some user friendly alternatives such as:

Smoothwall http://www.smoothwall.org/
Firestarter http://firestarter.sourceforge.net/
Guard Dog http://www.simonzone.com/software/guarddog/
IPCop http://ipcop.org/
Astaro Security http://www.astaro.com/firewall_netwo...urity_solution

Intrusion Detection:
Snort http://www.snort.org/
Sentarus http://www.demarc.com/
NetDetector http://www.niksun.com/Products_NetDetector.htm
Tripwire http://www.tripwire.org/
McAfee IntruShield http://www.mcafee.com/us/enterprise/...ion/index.html

Visual route:
AET Tracer Pro http://www.aetdata.com/tracer/
Visualware http://www.visualware.com/
GeoTrace http://geotrace.sourceforge.net/
S-Trace http://s-trace.sourceforge.net/

Rootkit protection:
Rootkit Hunter http://www.rootkit.nl/
chkrootkit http://www.chkrootkit.org/

System integrity check:
Bastille http://www.bastille-linux.org/

Access control:
Novell AppArmor http://www.novell.com/products/apparmor/
Novell Identity Manager http://www.novell.com/products/identitymanager/

Biometric security:
Eyenetwatch http://www.eyenetwatch.com/biometric-security.htm
VeriFinger/FingerCell/VeriLook http://www.neurotechnologija.com/index.html
IrisScan http://www.iriscan.com/index.php

Additional Links:
Insecure (News, tools) http://www.insecure.org/
Security Focus (News, tools) http://securityfocus.com/
Linux Security How To http://www.tldp.org/HOWTO/Security-HOWTO/