as for a dual processor machine you would need a dual processor motherboard, and two multi-processor cpus (ie, AMD MP 1400). and then for an OS, in the world of windows you would need a NT based operating system (NT, 2000, XP pro) as they support multi-processors..

one note, if you have two 1ghz cpus in a dual cpu setup, your speed still doesnt equal 2ghz.. provided the software is written for it, they basically balance the load between the two.

What is the specs of the first system you listed there? a 386 is a fairly outdated system, but some parts may be salvagable, hard-drive, cdrom, mouse, keyboard, monitor, etc.. the rest you may be able to sell on e*ay for a few bucks..

lastly, a dual processor machine would access the net just as a single processor setup..

-scoob8000