Remote car starters have long been a favorite among denizens of cold climates. Now you can use your iPhone to warm up your engine remotely, thanks to the Viper SmartStart from Directed Electronics. The system, which requires hardware that must be professionally installed in your car, also lets you lock and unlock doors, pop the trunk, and set off a panic alarm. Unlike existing remote starters, it works from anywhere, as long as your phone and car have cellular connections. Cost: $499 for the complete kit; if you already have a compatible Viper system, you can pay $299 to add the cellular component.