How long are you banned for chat channel spamming in World of Warcraft

This all depends on the severity of the spam and if it was your first time. You should have gotten an email from the world of warcraft gamemaster that banned you. The ban can last anywhere from 3 hours to forever (again, depending on the severity). The GM's can be pretty forgiving of first time offenders, but have been known to give out more lengthy punishments for repeated infractions.