Power source is easy, but don't make him search for the dang signal light wires!! That's mean

lol
Here's a great link, bookmark it, I did!!
http://www.aleromod.com/forums/showthread.php?t=19347
From there you can find wiring diagrams for your car, and more specifically, the exterior lamps circuit: (if this works)
http://arrc.epnet.com/autoasp/framerq.asp
You might have to do some testing, but it looks like, at the multifunction switch (on the column) you can tap into the ltblue/blk, and dkblue wires for left and right respectively. HOWEVER! They are almost assuredly ground control wires, meaning they give ground, not power. You will have to wire the mirror signals up for constant 12v in, and then the ground side will go to those two wires.. the LED turn markers shouldn't draw enough amperage to cause any issues with the circuit.
MAKE SURE THEY WORK LIKE THAT FIRST!!!!
When you find those wires, get the multimeter out, and backprobe into their pins on the harness.. where ever it is. Set the multimeter to read voltage... put one lead on the backprobe, and one on the battery. Should read 12V. Turn the blinker on, and it should read 12V with it off, and 0v with the blinker on.... on the multimeter it'll just look like number bouncing between low and high.. but that'll prove it's giving ground.
If that doesn't work just hollar and I'll think of something else for ya :P
BTW.. if you want power... just use a fusetap, those are the best for small things like this!!