This is a parody but the actual process of water boarding is described spot on
http://www.youtube.com/watch?v=-GcXl1y_mQw
Reporter experiencing waterboarding
http://www.youtube.com/watch?v=4LPubUCJv58
Radio host who says it's "not torture" experiencing waterboard for the first time
http://www.youtube.com/watch?v=qUkj9pjx3H0
So after watching waterboarding scene in The Expendables I researched it a bit and looked up other videos about it. It's vastly underrated in all ways by the average citizen. Top CIA agents can experience 14 seconds of this. That's one time. There have been cases where sleep deprived and starved prisoners have been waterboarded up to 143 times.
In my opinion this is the definition of torture.