I needed to extend my SharePoint Dev image to also include the incoming e-mail option, and without the need for an Exchange server. I'm not an e-mail/SMTP guru so this had to be done "the Google" way, and once a again: "success"!
What do you do? Read Getting email functionality with MOSS without Exchange on PlanetWilson Sharepoint. It also works on Domain Controller+MOSS 2007. Just make sure you get the domain names right both when setting up MailEnable and the local SMTP service (in IIS).
If the e-mail doesn't show up in the list after you have gone through all the steps make sure you also check your library's security settings. "I changed the E-mail security policy for my library to archive all e-mail regardless of sender and was able to receive the e-mail into my library. This made my gray cells to work! I was sending this email from my production domain account and though that account is made administrator in my MOSS2007 on dev it didn't recognize the sender beeing authenticated member. I changed the E-mail security back to Use document library security for e-mail and created new email with dev account and the email was created in my library. Conclusion is that this is working accordingly and you need to keep in mind the E-Mail Security settings for doucment libraries." Link here
If you would like to use Exchange then check out the whitepaper from Combined Knowledge for how to the configuration. Read "How to configure Incoming Email Enabled Libraries in MOSS2007 RTM using Exchange 2003 in an Active Directory Domain." It walks you through every step for a successful configuration .
When and why to use e-mail enabled document libraries or list? Read some comments from Joel Oleson.
Then it's time to create some SharePoint 2007 MailIn solutions!
Then you should check out the following articles/links:
Something you want things to happen, but your code is either executed to late or too early when you try a data bind. Read this article and you will get it right at once.