Exchange 2003 on SBS.

Ok, we are getting ready to change the DNS settings so we can host our own exchange. Currently, we are using Intermedia. Another company is in charge of our domain and is going to make the switch for us.

I've set up the mailboxes to be replicated. Is there anything else I need to do specifically? Our local domain is something.local. But the email will need to be something.org.

My main question is this? Should we be able to send email with our exchange server even before the DNS switch? I know we can't recieve mail, but I thought that sending mail was entirely different.

Any light you could shed on this would be greatly appreciated.

Thanks.