My BB has several mailboxes that seem to keep duplicating emails, let me try to be specific.

1. I have an Exchange email account, yahoo account and gmail account.

2. The exchange emails come to the exchange account, a desktop account and to the messages folder.

3. The Yahoo emails go to Yahoo and messages, but then show up in the desktop folder once they are downloaded into entourage.

Is there any way to stop the madness? Just one account for Exchange, one for yahoo and one for gmail. Then whenever I open the accounts they are alwasy current vs. a whole bunch of duplicates showing up both when entourage is open and when it is closed...

The MESSAGES icon is a catch-all for all messages.
you cant seperate them.
Look for an app called Empower, which may be useful.

What's the "desktop account/folder"? In the beginning you mention that your 3 accounts are Exchange, Yahoo and gmail.

As MidnightDraven said, Messages is a catch-all so that's expected.