Outlook 2003

[Guest]

I use 4 email accounts, all of which have separate folders
in my Inbox. 2 questions:

1. I can only send emails from 1 of the accounts. Even when
I open another account and click on New Message, it always
is from the one account. Any ideas on how to email from
the 3 others?

2. Whenever I send a message to the different accounts
(either from Eudora, or from within Outlook 2003), I always
get 3 copies of the message in each account inbox.
However, when I use the Test Account Settings in the
Tools/Email Accounts/Change Existing Accounts I only get 1
email.

Is there any way to only receive 1 message when I send to
myself?