Well you can either dual rush or dual.
I'd think that you are referring to GOW for dualing.
here's my build order for dualing (regular)
peon 1-townhall
peon-1 farm
train peon 2
peon 1- start second hall
peon 2- build farm at original town
peon 3- go over to expansion and build mill or rax in wallin spots
peon 4- build the building you didnt' build at peon 3 and put it at wallin spot on either expansion or regular
by now your farm from peon 2 should be done
basically keep on building farms to wallin on both bases and get keep at 22-26 peons

For dual rushing just do the above and substitute mill with smith. Constantly train peons from both hall and get grunts only when you have extra gold. You can hide the grunt to take out any cat or actually preform a rush with it.

thanks for the advice "sigil". i appreciate the order, and i will use it today when i play on bnet.

Horn

I would like to know as many dualing strats as possible, as only one can be defeated using a certain strat. Please respond if you wish to opine on this matter...

Horn