I just had a search around, and this looks like it might help you on your way:
http://www.annoyances.org/exec/show/article04-101
It will be pretty straight forward to do the wake on LAN between computers on the same network. It gets a little harder to get it to work across the internet - you need to get through the your firewall etc. That's where I stopped last time - I just leave the PC on!
The remote control software can be got here:
www.realvnc.org
There is a good FAQ on the site. There are lots of other versions of this software but these people are the originators.
Have fun
Memetic.
edited to correct a url...