Does anyone know what is the name of a pipe or channel that you can slide cables through it, so you can hide the cables from view? This is for the wall because I have cables dangling all over the ceiling and adjacent walls. Any clue where to buy this?

There are tons of things at home depot that you could use for this purpose. Go into the plumbing sections and look around. Also, for distances under five or six feet, they make plastic covers that slip over rusty showers rods - these are excellent for cable management.

If you want to run the cables in the wall to ceiling corner, one great way to do it would be to use crown moulding. you could run the cables as you hang the moulding - it could improve the look of the room a lot as well. If you go this route, I would buy the styrofoam-like moulding that is man made. It looks just as good, but might be less flammable.

Also, check out http://www.panduitncg.com/solutions/surface_raceway.asp