Starting in 2009, Lenovo's ThinkPad laptops will be programmed with a feature that allows a stolen or lost laptop to be completely disabled by a simple SMS text message. It's reversible: if you somehow manage to reclaim your laptop, all data and functionality can be restored by a resurrection code.
It's a nice little security feature, but the drawback is obvious: your laptop needs to be tied to a data plan and contain an installed WAN card. So the extra security has a monthly fee. It also means the first thing canny thieves will do when they steal a Thinkpad is pop out the SIM card, but there's realistically slim chance of that: most thieves are idiots. Still, wouldn't a better security measure be not only to disable the laptop, but secretly phone home with location coordinates once the code is activated?