I use a Manfrotto 420B Combi Boom Stand to hold my camera overhead while I film.  Think of it like a big tri-pod. I like it because I can move it around and it folds up for easy transport. I do not zoom while I am working but make the adjustments in IMovie during the editing process.  I use a Nikon D5100 for filming and since I am filming in HD I am able to zoom after the fact without losing quality.







This is the counter-weight that hangs on the back.  I just put a brick inside of it.



Since I keep my camera strap attached to my camera, I use a hair clip to hold it to the bar so it doesn't hang down.



I use a Varizoom VZSHOE Shoe Mount to attach the camera to the boom. It simply screws into the bottom of the camera and there is a little "handle" that moves the mounts around so you can re-position the camera.

I don't use my IPhone so I am not sure which mount works best but I am thinking something like THIS might work.