Picking a turn based game to play online

Hi,

Just picking the collective brains of the forum, as I'm looking at getting a turn based strategy game to play with a friend online.

I'd like a game that can be played in stages, say for example I take a turn, close the game and come back a few days later once my friend has taken theirs. I haven't played turn based before, is this a standard feature in something like Civ IV?

Thanks in advance for your advice...