Hey Mike,
The busiest place for OCS info is at consimworld:
http://talk.consimworld.com/WebX?13@231.s5one6RMPYT.6@.ee6b471/27444
I'd answer your questions, but I've already talked to you a lot about it.
What the hell, I'll give my thoughts anyways...
People seem to agree that Tunisia is the best
campaign to start with, but it sounds like there are a lot of
scenarios in other modules (like the Chir Battles) that are good for learnin'.
I've been playing PBEM Tunisia, and it works very well. A lot of OCS play time is spent moving units / supply around, in preparation for an attack, and there's no need for the other player to interact. So that works well. There are a few more back-and-forths when combat starts, because your opponent isn't supposed to look into your stacks (ever when attacking them!) You announce your action rating and strength points after the attack is declared.
I'd imagine you could speed up pbem play by getting rid of this rule, but I personally love all things fog-of-war, and I think it's worth it.
There are quite a few players at consimworld who play by email, and it sounds like they all do it slightly differently, depending on how fast they want to play, and how much fog-of-war they want.