Yes, you'll be able to play the Wii version of Call of Duty: Black Ops online -- and even use voice chat, if you happen to have the proper equipment. To that end, PDP has announced the $25 "Headbanger Headset."
Conveniently, PDP is releasing the headset on November 9, timed with the release of the game. It'll be available in white, or in a "limited edition" Call of Duty: Black Ops version -- meaning: in black with the game's logo printed on it. That way, when someone asks you what you're playing, you can simply point at the side of your head, without the need for more conversation; which is good, because nobody would want to talk to you after that.