the addon is called TellMeWhen.
it is mainly a caster addon but you can use it for any cooldown you have on your self or on your target.
The timers can be set with the show buff/debuff it self.

I use it with my warlock, mage, Shadow priest and Hunter.

hehe i am using a similar spec....but mine is based off the 3rd best geared person on Blade's Edge realm (ofc he is a hunter)....the only difference between the one i copied and Dorkins is it sacrifices Imp aspect of the Hawk for 2 points in Hunting Party so replenishment is ALWAYS up whether its mine or someone elses...plus i don't think the +3% to your attk speed is really worth it...anyway here is my spec : )
http://www.wowarmory.com/character-talents.xml?r=Blade%27s+Edge&cn=Zidius&gn=Blood+Reign. ..ignore the blues i have been to busy as of late (work) to do heroics and get better gear...though i was able to perform well enough in a guild Heroic Naxx run that noone even cared i was in blues (only about 2.1k DPS raid buffed which was better than another hunter they have run with who has epics and could only pull about 1.6k)