sorry for being a noob..but i still dont get it.
can anyone who has added the volume pot post some pics on how u do it?
I'll elaborate on Aron's description to hopefully make it clearer:
He must have wired the 100K as a volume pot. 10uF to outside lug, wiper to output jack, other outside lug to ground. Reverse outside lugs if backwards.
You see the 100K resistor that is between the 10uF cap and the output? Replace it with a 100K potentiometer (preferably audio taper, but linear is okay too).
Break the connection between the 10uF cap and the output jack.
Connect one of the pot's outside lugs to the 10uF cap.
Connect the other outside lug to ground.
Connect the middle lug (also called 'wiper') to the output jack's tip lug.
If the volume works backwards - so the level gets lower when you turn it up - that means the two outside lugs need to have their connections swapped.
Here is more info on wiring pots that may help you get the connections right the first time: http://www.diystompboxes.com/cnews/FAQ.html
Lug 1 is the one that usually connects to ground.
Hope that helps.