I was wondering if anyone knew which file actually spits out the signature in pnforum when the 'attach signature' box is checked? I've looked, but I can't seem to find it. I want to add a small line above it. Thanks for any help.

Check the common.php for the function pnForum_replacesignature

These seems to be where (at least in 2.0.1) that it attaches the sig to the end of the post.

Copy the innards of the function, comment out the original (so that you can go back easily), then place with the copied portion to see where you can add the desired content.

UHEweb

Found it, thanks uheweb. I'm using v2.6 and it's in the same place.