Channel is banned in every tourney format out there, and is way too cheesy a card to play on your friends. If someone is willing to give you an old Icy for it, you are seriously ripping them off.
Ah, if only Channel could be used to do what it was originally intended for... How the hell they missed the combo is beyond me however. Channel is great in an artifact deck with a lot of card drawing or activation costs. If only there was a way to put a lot of life into mana and then get that life back... Drain Life/Initiates of the Ebon Hand are just too degenerate though.
Actually, if you can get an icy manipulator, even an ice age one, for a channel you are seriously ripping someone off. And channel isn't a rare, it's an uncommon.