mystikmind2000: I tried multiplayer for SMAC years ago.
I forget how it worked but i do remember the 'offturn' player cannot do anything.... what i mean is, in addition to not being able to move units - which is obviously necessary... you cannot do anything else either! cannot even look in the city screens!!
So you might want to keep a second computer handy, so you can entertain yourself while the other person is having their turn.
IIRC SMACX allows for either sequential and simultaneous multiplayer (as well as some Play-By-Email support for sequential, probably not simultaneous). But IIRC simultaneous is sometimes glitchy, and this kind of game is better played in sequential anyway : you don't want your battle plans messed up because your opponent was faster at moving his units at the start of the new turn than you!