Written by the guy who wrote Roguecraft 101 over on EJ.
It's a bit more accurate than Aldrianna's, IMO. I was surpassing Aldrianna's estimated DPS on Teron for my gear; on this, I'm not meeting the potential, which is about right.
http://elitistjerks.com/f31/t27244-rogue_roguecraft_spreadsheet_beta/
Edit: To show how scary-accurate it is, I put up 1774 DPS on Teron, it estimated my DPS should have been at 1807 with the buffs I had. Considering I wasn't using an optimal spec, that's pretty damn accurate.
Edited, Jun 19th 2008 4:23am by Theophany