Games are played by correspondence on the site so you can set x number of days for players to make a move when it's their turn. AW can look a bit overwhelming at first with all the different units, terrain types, and so on, but you can get the hang of everything within the hour at most. The cartoonish graphics I think make for a really relaxed atmosphere, unless you're the kind of person who can only play super serious RTS titles(!).
Advance Wars is a turn-based strategy game created by Intelligent Systems and distributed by Nintendo. You command an army of land, sea and air units which do battle against your opponent [up to 8 players can face-off on a map]. This version of Advance Wars is a bit of an amalgamation of Advance Wars, Advance Wars 2: Black Hole Rising, and Advance Wars: Dual Strike. Many of the features that are in those three games are implemented here.
My username is Godoc so feel free to throw me any spare game invites if curious.