I use sleepover but all the iphone progs are basicly the same ..I use it every day in the morning to wake up my computer thats turned off so its ready for me to skip through the forums before I rush out the door to work and also on my way home from work so the computer is fully booted when I get in the door works very well..
I think the biggest issue when setting this up to work is when you are using a router and you want to wake the computer from the internet most routers dont have the option to set up to broadcast over the lan or manualy set a static arp as when the computer is shutdown there is no ipaddress being kept alive on that machine and when the router arp cache is flushed theres no way to sent to that computer to wake it up, if you can configure your router to broadcast over the lan then it will work fine or even better if you can set a static arp route it works great.. also you need either a static ip address or use something like dyndns if your going to use it from the internet..
If any of you guys have a router which allows to do port forwarding for UDP port 9 to the broadcast address of your lan (for example: 192.168.1.255) try it. As g0sbv said, you'd need a public IP address or a dynamic dns service.