So is Dual Boxing legal or illegal?

Q u o t e:
These forums have the most horrific search feature on the internet. I have yet to get a single result, no matter what I search for.

Hyperbole. It's frequently (and purposefully) disabled, yes, when incoming player traffic is high, but it's not "the most horrific search feature on the internet." If it were, I'm sure we'd have received our Golden Dump Truck in recognition by now.

That said, here you go:

Botting vs. Playing Multiple Accounts Simultaneously
http://forums.worldofwarcraft.com/thread.html?topicId=3168405460&pageNo=1&sid=1#9
http://forums.worldofwarcraft.com/thread.html?topicId=5288579356&pageNo=1&sid=1#2

Hope it helps. :)