assumptions:
1.You are trying to play multiplayer civ with a freind across the street,town,city etc.
2.You both have internet access
3.You both have a multiplayer version of the game
4.You both have the latest patch(available here in the d/ls collection)
5.You both have an instant messenger of some kind(icq,aim etc)
First thing is to setup the game.Start multiplayer game etc.Select "Internet Game".Each window is fairly straight forward.
When you get to a screen like this:
copy and paste that ip address into your messenger and sent it to your freind.He/she then enters it in a similiar window thru the "join game" menus.
Before doing that though,continue to this window:
Now just wait until you see your freind's name/handle appear.This may take several minutes.
Start the game and the next set of windows you will have seen before as you select your civ and what not.