For quite a while, you've been able to get security lights with timers that automatically come on at night and go off, to make burglars think you're home when you're really not. And you can also get programmable timers, so that the lights go on and off at times of your choosing, not always at the same time every night (someone staking out your house while you're gone might become suspicious if your lights turn on every night at precisely 7:00 pm). But now, even more sophisticated security lights are available.
You can buy whole-house home automation systems that turn lights off and on automatically, different lights in different parts of your home (inside and out) at different times, all without you having to be there to do a thing. You can even integrate your lights so a microprocessor remembers your lighting habits for two weeks and replicates them when you leave for vacation.
Yup, lights on timers are a whole lot smarter these days. If you've got a dated system (or no automation whatsoever), it might be time for a security upgrade. And if you enjoy various aspects of home automation, you might even have fun planning it all out.
Lots of stores, online and off, sell the equipment to get you started, so just get out there and look around. There are also magazines on home automation that can be great resources. Just browse through Borders or another big book store with a large magazine section, and you'll have no trouble finding ideas.
Outdoor lighting in your front, back, and side yards is an excellent way to deter burglars. They prefer to do their work in the dark and shadows, so a well-lit yard can make your house a less appealing target. However, it's unlikely you want to run your energy bill up by leaving the outdoor lights on all night long (your neighbors may take exception as well if your floodlights are shining into their bedroom window). 
Lighting in your front and backyard is a good idea for home security reasons. A burglar is not going to want to ply his trade at the well-lit house on the block, when he can skulk in the shadows of a darker yard across the street. And, of course, lighting makes it safer for you when you're walking up to the front door at night (nobody can hide in the shadows to mug you if there aren't any good shadows!). 
It's a good idea to have lights that go on automatically at night even when you're out of town. This way burglars are more likely to believe someone is at home even when you're not. But if your lights go on at the same time everyday, such as 7 p.m. on the dot, a burglar who is paying attention might figure out that nobody is home.
f you've ever heard someone or something rummaging around in your backyard or frontyard at night, you've doubtlessly wanted to see what it is, but maybe you're not keen on walking through the house in order to get to the kitchen, front door, or wherever the light switch is for your outdoor lights. The Insteon Outdoor Safety system lets you operate your yard and porch lights from any room in the house with a tabletop controller. If anyone is out there snooping around, turning on the lights will likely scare them away. With this system, you can do that without even getting out of bed. 