Just a quick note... If you are a MOSS dev setting up a new development environment on Windows Server 2008, you might have noticed that there is no POP3 service anymore. This makes it a bit difficult to shows workflow with email notifications, etc if you don't have the ability to have a user mailbox. And of course, you don't want the full blown Exchange app there because of the bloat on the VM and performance. Try out this free one:
I'm using it for both SMTP and POP3 with MOSS configured for outbound messages. Note that I didn't say inbound. For MOSS to do that, you have to use the SMTP in IIS. I didn't need that so sticking with this for the time being.