George, you are talking about two different things.
1. Setting an app as the default email app.
2. Downloading your email.
Harv gave you the method for handling number 1. Strange as it seems, Apple expects us to always have a usable copy of Mail around just to set the desired email program we want.
Many email apps come set up to automatically check/download your email when they start up. So, if you open Entourage, it goes and gets you mail because it thinks that's why you opened it.
However, you first asked how to get Entourage to be your default email app. Are you now saying you really want Apple's Mail to be the default?
How to find out what app is set as the default email program:
1. Close
all email programs.
2. Click on an email link on any web page.
3. Whatever program opened is what the OS thinks should be the default email program.
If it's not the one you want, follow
Harv's advice. Then check the prefs in that program and decide if you want it to automatically download your mail or do it only when you ask it to ( since I'm a control freak, that's the way mine are set up!
).