Need to move approximately 12 email boxes from a sister company's SBS 2003 to our company's Exchange Server 2007. Both companies are in different domains and both reside in their own forest. Moving the users at our sister company into our company's domain is not an option so our Exchange Server will have to provide email services for users in two different domains (sister company and ours). Once the move of the mailboxes has been completed Exchange on the SBS 2003 server will be turned off. While I am familiar with Exchange I have never down a transfer across domains like this and would appreciate either a step by step guide to the process or a link that points to same. Thank you!