I couldn't find any straightforward information about how to do this anywhere else, but I was wondering if anyone knew a good solution to my situation:

My boss currently uses Thunderbird as her primary email client (has a GMail/POP3 address), and sometimes just uses GMail from the web. We send out a lot of mail-merge emails and want to configure Outlook 2007 on a separate computer (but linked through our network to my boss's computer) to only send out outgoing mail-merge mail, not receive or download any incoming mail. Is there any possible way to do this? Thanks so much in advance!

Create the POP3 account in Outlook. After creating the account and while viewing the Inbox, press Alt-Ctrl-S. Select the send/receive group (usually All Accounts) and click Edit. Select the account you added and uncheck the box labeled "Receive mail items".