How to Setup Mail Enabled Document Libraries in SharePoint 2010
E-mail is an integral part of any SharePoint installation as it is the backbone of communication with in a SharePoint farm and its users. Needless to say, it becomes imperative for any SharePoint administrator to know the basics of configuring the SharePoint environments to send and receive emails.
Dave Coleman (Microsoft MVP) has an excellent series of blog posts which provide step-by-step instructions to setup incoming and outgoing email. You can access it here.