NEW YORK ( MainStreet) -- Super-luxury estates don't just come with swimming pools and tennis courts these days, but also boast elaborate home theaters and special controls that can unlock doors or adjust thermostats even if you're halfway around the world. "I'll walk into a dark house with a buyer, press one button and turn on the lights, the music and the home theater downstairs," says Debra Johnston, an Atlanta real estate agent who specializes in high-end properties. "The whole house is ready to go -- and the client can see that." More and more high-end properties feature such "smart-home" technologies - professional-grade audio/video systems, plus lights, thermostats, window shades and more that you can control with an Apple ( AAPL) iPad or other smart device. Such systems not only let you to change the TV's channel remotely, but make it possible to check security cameras or open the front gate for a repairman even if you're thousands of miles away. "You can automate pretty much anything in the house -- lights, audio, heat, air conditioning or the security system," Johnston says. Here's a look at five of the poshest smart homes listed for sale on Realtor.com, the official site of the National Association of Realtors.