I've been looking on how to control power outlets through wifi and I've only found Belkin's WeMo. Are there any alternatives?
Home automation is on the rise now a'days with the advent of smartphones and with wifi becoming more popular in houses.
On the low end, you have equipment like the x10 Commander - this will allow you to control x10 devices from an iPhone / Android phone over WiFi. The commander acts as a bridge between WiFi controllers and x10 devices.
x10 devices can control lights, outlets, thermostats, etc...
On the high end, you have equipment like Crestron; these systems are more expensive, going well into the $1000s and usually used in higher end restaurants and hotels but their not unheard of being used in homes and are more common in higher end homes. These systems can do everything x10 devices can, but are much more advanced with table top displays, ability to schedule events and lighting patterns, etc... Usually a central command unit is required and should be installed by a professional.