I would like to SSH to my home computer (Mac Snow Leopard) but I don't always know if it's on. I have enabled wake on LAN. Is there a way to wake my computer (or check if it's awake) from the command line?
You'd have to have a second, awake computer (or WoL-capable router) on the LAN to send the magic packet. It is Wake-on-LAN, after all.
The router method is easier. Check out this DD-WRT article to get it going.