Yup, I botched up that link ...
If you type surface skimmer in Big Al's search you'll find it.
So basically the skimmer is an additional water intake? Does it remain under water or partially on surface? Is it noisy? I'll have to take a look at the packaging at the lfs.
The answers to your questions;
1> The "basket" (for lack of a better term) floats
on the surface. It can slide up/down but it is always floating on the top.
2> It makes no noise at all. It is adjustable so you can set how much water is drawn from the top versus the bottom. It may get louder if you set it for 100% up top. (But the noise will only be the water falling into it.)
Just a bit of background for you...
I have a 35G "swim-thru" tank. It is basically 2 separate tanks with two tubes so that the fish can swim from one to the other. I have a Fluval 304 and it is rigged up so that the intake is in one tank and the output is in the other. What ended up happening, was that the intake side was just drawing water in, but there was no surface agitation and a "film" was developing on the surface. I was concerned about the oxygen exchange.
I added the skimmer and it cleared up in a couple of minutes.
I'd recommend a surface skimmer to anyone.