Can I setup in Exchange 2003 an account/group that will email (2) different accounts outside my domain?

Yes it is possbile.

First Create a contact in AD users and Computers with 1st email address.
Once created. Go to the Properties page of the Users.
Go to the Email Addresses Tab
Add the 2nd  SMTP address you want.(You might have to add the 1st email address again if needed)

Hope this helps

Do you want to send an email and have it go to two addresses automatically or do you want it to be sent from two addresses automatically?

I want to send an email to (2) addresses -

In that case you can follow, the steps mentioned above

I would say create a group in outlook and just add both addresses to the group and then just send and add the group to the To: field

I added the contact and added the email address for 2nd contact - I am testing using my (2) yahoo accounts - The "primary" email account w/ the capitalized SMTP received the email but the 2nd emaill account did not receive the email -
 
I have used this step for persons in my domain (company) with named changes and it works fine but it appears not to work w/ accounts outside my domain -

Any ideas - Thanks for input so far -

I created a Universal group which allowed me to choose from "contacts" - thanks guswebb!!