Hi! Take a loot at my page
http://www.facebook.com/pages/Sergio...nn/55050982059 and listen to the second track, "Diablos Rojos Porra Batucada". If that's the effect you're looking for, a sort of stadium-crowd chant effect, then record yourself singing different harmonies to the same melody and then move each track a LITTLE BIT (to taste) forwards or backwards. Remember, in a stadium people don't start singing at exactly the same time!
Hope that helps!