There is a chat feature, asnd the turns are made instantly, games take anywhere from 30 min. to 3 Hours.
You can get up to five players in a game.
It has been awhile since I was on the Zone, but there were always between 30 and 100 people there when I looked. Games were fairly easy to get. The best way to insure you get games is to join an online club like Spring1942.