Since I heard about the rare spawn Loque'Nahak (spirit beast), ive been desperatly trying to find and tame it. However its proving too hard.

Noobs keep killing it. Other hunters keep taming it.

I must have seen it killed or tamed infront of me at least 10 times by now. Its so fustrating!

Is there an addon which could help me get the upper hand, by alerting me when the creature will spawn and were it has spawned?

And if not would it be a good idea to make it?

Nope. each rare mob has a few spots where it will spawn and they all seem to be on long timers (6, 12, 24 hour). If you do a search on Wowhead.com and see =if anyone has figured out the spawn time and locations then, if you know exactly when it was killed last time you "may" have an idea when and where it will spawn. This is not secret information so you may not be the only one sitting there waiting for it to spawn. GL.

used to be an addon called Rare Finder would give you an alert when you moused over a rare, but don't think it works anymore. It frequently helped me 'accidentally' find rares that I'd otherwise would've missed.

I wrote my own Addon to do this.

http://www.wowinterface.com/downloads/info12758-ESNRare.html