I figured I'd post this here as well since i didn't really see anything about it in this thread.
Solenoid Wiring:
Black: Ground
Red: Hold-In low current
White: Pull-In high current
Grounding:
I would suggest starting off building a new ground strap/wire for the relay, the ECU, and the Solenoid (Preferably 10ga or 12ga wire) tapped onto the the existing ground strap on the front drivers side corner of the engine bay. That way it gives you a clean chassis and battery ground. My dash started giving me errors and no gauges because with my new bracket for my ECU wasnt properly grounded, so i would suggest running a ground strap to it.
Hold-in
I used the existing key on power wire out of the stock
VP44 plug harness for the hold position. If you look through the wires on the plug it should be the Red wire with a green tracer (at least this is what it is on my 99 (take a second and check with your voltmeter.
Pull-in and relay
I tapped the starter trigger wire; it's REALLY easy to find since the plug for it is just clipped to the fuse box in the engine bay, it should be a brown wire coming out of the sheath of the positive starter cable. Just run a branch off of that to your relay of choice. I used a 30A generic relay from schucks. I would suggest tapping a positive power wire out of the fuse box on the fused side of the main line coming into it for the solenoid.
If I find a digital camera to use i'll try to get some pics up (mine came to an unfortunate and very early fate at a game of drunken miniature basketball).
-Brendan