Damon Cooper, my boss, and Director of Engineering for ColdFusion recently installed a new Sprinkler controller at his house. It is fully net enabled, and is controlled via the Web!
I just recently got a new house, which needed a new lawn, so I put in a sprinkler system. While I haven't received a water bill yet, I am getting hives just thinking about how much water is wasted by my twice a day (new lawn remember) watering schedule.
If it works out for Damon, I suspect it wont be long before I spring for this system too.