Appeals Committee. Disputed situations in tournaments.

Two players are playing, with a third player acting as a helper. One of the players logs into an ICQ/chat. They receive a hint from there.
Question: Is this considered cheating?

No, because it's paranoia (IMHO). I see the chain of questions you're trying to build. To preemptively answer, the player giving hints doesn't "feel" the game the same way the player actually playing does, and very often the hints just distract. The question is different if another person is playing for the player.