Informative:

Burglar Alarm Wiki – Wikipedia should always be the first place you look.
How Burglar Alarms Work – from howstuffworks.com, they describe how burglar alarms work.
How Lock Picking Works – another information howstuffworks.com article on lock picking.
How do motion sensing lights and burglar alarms work? – It isn’t magic, there is some science there.
How Safecracking Works – Ocean’s 11 and Mission Impossible comes to mind.

How-to Guides:

How to Discourage Burglars – guide on how to make your house less likely to be burglarized.
How to Install a Lockset – if you buy a new door, you need to add a lock to it.
How to Install a Home Security System – a how-to guide on installer certain DIY home security kits.
How to Use a Driveway Monitor Alarm – know when someone is lurking around your driveway.
How to Protect your Home with a Heat Detector – DIY heat detector sensor installation.

Build Stuff Yourself:

Protect Your Home with Laserbeams – video on diy laser beam alarm.
Super loud security alarm – instructions for building a motion detecting alarm that speaks to you.
Passive switch alarm system – guide for improving a magnetic alarm on your front door.
Home Built DIY Home Security Alarm System – a fully functional diy security system.
How to make an All in One Detector – it detects smoke, heat, and intrusion.
15 minutes SMS door entry alarm – build a cheap alarm that notifies you using text messages.
Designing a Home Security System – enough said.
Increase a Home’s Security – step by step guide with 3 in-depth parts.
Install a Security Light – install a motion-sensing security light.

Security Forums:

diysecurityforum.com – diy forum.
diyalarmforum.com – another diy security forum.
forums.securityinfowatch.com – for security professionals, in all walks of life.
forum.safemart.com – community on a website that sells wireless security systems.

Home Defense:

Choose a Firearm for Personal or Home Defense – many people buy guns to feel safer.
The Best Guns for Home Defense – a guide for choosing a weapon to use for home defense.
Defense of Home – a very American page on home defense.
Shotgun recommendations – blog post for beginner shotgun help.
Home Defense Shotgun – review of one of many home defense shotguns.
Bushmaster Home Defense – top gun manufacturer can’t be wrong, now that’s intimidating!
Ultimate Home Defense Loads – Remington provides you with rounds specifically for home defense.

Self-Defense:

Self-Defense Blog – on martial arts and defending yourself.
Self-defense Sense – Self-defense and security in an unsafe world.
No Nonsense Self Defense – lots of good info on self defense here.
Women’s self defense – that’s all folks!