Setup email enabled document library in sharepoint

http://blog.sharepointedutech.com/2010/10/20/how-to-setup-mail-enabled-document-libraries-in-sharepoint-2010-part-1/
http://sharepointquester.com/2012/07/24/configuring-incoming-email-on-a-sharepoint-2010-document-library/
http://technet.microsoft.com/en-us/library/cc287879

Read contents of emails in this document library

http://sharepointbrian.com/2011/04/custom-activity-for-sharepoint-designer-2010-workflow-get-email-body/

http://social.msdn.microsoft.com/Forums/en-US/sharepointcustomizationprevious/thread/45e70817-cb3a-4a75-af3d-7f4f014db428