Replacing alternator in 97 Yukon

I need to replace the alternator in my 97 Yukon. The one question I have is what is the best way to pull back the serpentine belt tensioner in this vehicle? It appears that I need to turn it towards the engine, but what is the best way to do that? Squeeze a wrench in between the engine and the idler pulley and try to get it on the idler bolt or is there a better way? Thanks for your time.

See page 2 of this article: http://autorepair.about.com/library/weekly/aa071205a.htm

//2000CAYukon

Thanks for the link. I took a second look and saw the square hole on the front of the tensioner. The hole is sized for a 3/8" drive ratchet or breaker bar.