yeah they toss em about all over the place! Its done by using their throat i think

Hehehehehehe, I wish I knew. I can't even figure out how they talk without moving their lips.

They don't actually throw their voice. They have practiced speaking without moving their lips so that when the ear hear sound and your eyes see no movement, your brain is fooled into thinking the sound had to come from someone else. When working with a puppet, this can force your brain into thinking, the mouth on the puppet/dummy is moving with the sound and the mouth on the vent (ventriloquist) isn't moving so, it HAS to be coming from the puppet/dummy. Some vents are very good at making voices sound farther away or nearer or in a hollow place or ... and this makes them very good at practical type jokes as they don't need a puppet/dummy to draw your attention away from their mouth. if you try the alphabet with your upper teeth pressed gently to your bottom lip, you will find most letters are still able to be created without lip movement (muffled maybe but still there) but there are certain letters that under normal conditions, cannot be said without moving your lips. So, like a magician, they draw attention away from these and accentuate on other things: these include b, f, m, p, v, w. Again, the brain being tricked is important - "brain" becomes "thrain" or "drain". A college study a while back said that as long as all the letters are there and the first and last letters are correct, the words are generally recognizable 95%+ of the time by the average reader. Vents do the same thing - but not the first and last letter, but everything excluding the 'replaced' letters are the same so although we are actually hearing "He had thwain surgery this morning." we translate it into "He had brain surgery this morning." It takes years and years of practice to get really good and even then there are some signs that the speech is coming from the vent, so you (the vent) have to make with the puppet/dummy do so well that they won't look at your face.