Bit hard to describe as I don't have pictures, but for Nicola's cage I just soldered a big hole through the side of the bin, big enough to snugly fit her waterbottle spout. Since it's a very snug fit, she can't get a grip to chew on it, which is a bonus.
I tried using suction cups to keep it there, but they just kept falling off (they were quite old and well used, though :P) so I made a few smaller holes to the side of the large one and used some wire to keep it upright, as you would with mesh. Hasn't failed me yet.