UAVirgin - That is very strange behavior - I use Outlook 2003 myself and have around 14 accounts setup - as long as I pick the right account when I am sending email from it does end up using the correct SMTP server - of course its different issue that my SMTP authentication is different for the different accounts.

I am sure you have already done so - but I would advise you double check the settings - hopefully it doesnt need a re-install though.