Creating my own WOL Program

I recently wrote a console application in C that basically allows a person who isn't comfortable with a command line to use two command line utilities to start up and shut down a small group of WinXP computers remotely. This program uses system() to run "PsShutdown" to shut down computers and "mc-wol" to start them again. The program works just fine, but I'd like to boost my programming skills by writing my own shutdown and Wake-On-Lan functions. I've searched the web and didn't come up with much that made sense to me. Where should I get started with this?