Sorry about the basic diagram, but I didn't take any pictures of it, but we made this (me and friends) and used this.
It worked amazingly, and I thought i'd post a blue-print of it so if you feel like making one, then you can just print this off, or memorize it and whalla!

What I used to make it.
1)3 bottles
2)Fish Tank Air Tubes (Wal-Mart, 8 feet for $4, can be re-used lots)
3)Metal Pipe(as seen in diagram, you could use other stuff, but we used a pipe)
4)Duct tape (we used lots because we were high while making this, lol, but you dont really need much, just so seal the holes where the tubes fit in)
5)Lighter to make hole in bottle for pipe or slider

STEPS
1)Get supplies
2) Burn a hole to fit your pipe in (the black thing on the diagram) *MAKE SURE THE BOWL IS ABOVE THE WATER LEVEL, BUT HAVE THE OTHER END OF THE PIPE IN WATER*
3)Put water in bottles
4) put tubes in bottle, then seal the tubes in the bottle with duct tape *DO NOT TAPE THE TUBES TIGHTLY OR ELSE SMOKE/AIR CAN'T GET THROUGH!"
5)Light up and have fun! Great for smoking with 3 or more people, because then you dont have to wait long to takes turns.

Enjoy!