The timeframe is based on the type of game you play.

There is anywhere from Quickhost (After everyone turns in their turn the game hosts and new turns are availiable) to standard set times (24/48/72 Hour Blocks), hosting at a specific time of the day (Noon or Midnight daily) days you skip (Like the weekend), or a combination of the above (Quickhost enabled, but every 24 Hours, a game will host).

The average game is 1/turn a day game with different options availiable on weekends (Some quickhost, some don't host at all, etc).

Some PBeM's that I've seen are twice a week games.