I can't answer the question about "Wake on LAN" on your home machine, but you would most likely do best to solve this while the machine is running before you attempt to do so while the computer is sleeping.
VNC is pretty basic, you simply need to install software to control the server (machine you want to connect to), and the client (machine you connect from). This is typically the same download and it provides both features.
For Mac I find this wikihow article, http://www.wikihow.com/Setup-VNC-on-Mac-OS-X
On Ubuntu, there is a built in VNC client under Applications > Internet > Remote Desktop Viewer.
Make sure the server is up and running first before you attempt to connect with the client.
You will need to forward ports (NAT) on your router if accessing across the web, assuming this is what you are wanting to do.