[G4] How to put Mail in charge of my email?

[Raymond E. Hardy]

I'm running Tiger now and would like to give Mail and Address book a fair
trial. I've used Mail's "Scripts" to import Mailboxes and Address's from
Entourage to Mail and Address book.
Problem - In Mail's Preferences I've made Mail the default mail program. I
can't find a similar Preference in Entourage to cause it to become inactive.
Entourage seems to have the upper hand and Mail doesn't go and get the mail
- is that a nasty Microsoft thing?
Any suggestions?
Ray Hardy