I've done it. It requires a couple of butt connectors and a piece of wire.
For fogs on with the high beams, pull the foglight switch out and look at the bottom two wires. They're the same color scheme. They're both 12v ground wires, except one goes +12v when the high beams are on. Cut the upper one and connect the switch to a permanent ground (can splice the 2 wires together), and cap the stub from the wiring harness.
The next part is more difficult, and frankly, if I can't find my notes, I'm not going to tell you.
From my notes:
The connector on the fog light switch should have 5 wires going into it.
a) Blue/White - power with headlights only. Lights up the switch.
b) Black/White - goes to the relay to turn the lights on.
c) White/Yellow - has power when the parking lights are on. Dash illumination.
d) Yellow/Blue1 - This is YB1. It is normally a GND, but when you turn the high beams on it has electricity.
e) Yellow/Blue2 - YB2, all by itself at the bottom of the plug. It is the GND.
On the left side of the fuse panel there are two relays. I think they are round. The top one should have a pink connector. It should have a Blue/White wire in it that turns on only when the headlights are on. Test this. If so, cut it off, leaving enough wire on the plug to strip and connect to. Wrap the harness end of the BW wire in tape to avoid short circuit. Find an ignition controlled power source and splice two wires off of it. The first one connects to the B/W wire hanging off the relay.
Route the other wire to the fog light switch, cut to length leaving several inches to play with. Strip it. Cut the Blue/White wire on the fog light switch, leaving about 2" to crimp to. Strip the end, and butt-connect the BW wire on the plug to the power wire you just ran. Tape off the BW stub in the harness to prevent a short.
When you're looking for power wires, verify that you're not using a dashboard illumination for your source, because otherwise the fogs will turn off when you dim your lights.
Do it at your own risk, make sure no wires are exposed when you're done, and don't come crying to me if you screw something up.