Melee + Caster: How do I do it? (I've read the Wiki)

I'm doing my first dual-boxing and I'm debating on Paladin/Shaman, Paladin/Priest, or Paladin/Mage.

I've read the Wiki but I'm still completely unsure how to control two characters like this. It seems like it's almost easier to just use two keyboards but I'm not sure... If I do use two keyboards/mice on Vista, can I have each keyboard/mouse sent to one specific World of Warcraft window?

If I do use one keyboard/mouse (with KeyClone or Octopus) then how do I control the melee + caster?

you dont need two keyboards. just play the melee as your main and have the caster on follow. then at the beginning of battle knock the caster off follow to hang back and run in with melee using hotkeys and macros to shoot support spells while you are owning with the melee unit.

Yep, one keyboard.

Using keyclone you generally put your WASD movement keys on do not pass but leave your arrow keys off DNP. So your caster is merrily following the melee dude who you are controlling with WASD. You start to approach a mob, you tap the down arrow, which causes both toons to take a step back and breaks caster's follow. Then the melee runs in and the caster stays put.