The ability to couple an e-mail adress to a SharePoint list in both Microsoft Office SharePoint Server 2007 and WSS 3.0 is a very interesting feature and it seems there are a number of posts out there which describe how to do this. Recently a Screen cast about how to configure a SharePoint Server 2007 site to receive e-mail appeared but the best explanation still remains the white paper which Steve wrote - you can find it http://www.combined-knowledge.com/Downloads%202007.htm , he recently updated it to reflect the changes for RTM.
It is however also possible to use e-mail enabled lists with a simple SMTP server setup on a standalone server - listed below are the different steps required:
1. Install SMTP Server and configure it to relay mail
a. Open the IIS MMC snapin
b. Right click on Properties of Default SMTP Virtual Server
c. Click the Access Tab, Relay. Add the IP address of the SharePoint server to the computers that can relay through this virtual server.
d. Click the Delivery tab, Advanced. For Masquerade Domain enter the netbios name of your web server, for Smart Host enter the netbios name of your server that you are using.
2. Configure the incoming e-mail settings in WSS/MOSS
a. Open the SharePoint Central Administration and navigate to the Operations tab
b. Underneath the Topologies and Services categories - you will find a link to Incoming e-mail settings
c. Enable incoming e-mail and use the advanced settings mode.
d. Leave the Directory Management Services defaults as they are (No)
e. Fill in the e-mail server display address
f. For the drop folder put c:\inetpub\mailroot\drop - if you are not using the default settings you will need to change this
3. Configure the e-mail settings for a specific list/library.
a. Click on list settings for a specif list/library
b. Under Communication settings, click Email settings
c. Check the Enable this list to receive e-mails.
d. Fill in an e-mail address for the list/library