Microsoft have just released the BizTalk adapter for MS CRM 3.0, enabling connections to other software which have connectors to BizTalk.
I havn't tried it, but would like to, especially since the Tectura integration between CRM and Nav in many ways is incomplete. BizTalk is also a more general integration engine which enables connection to other ERP-systems like Oracle, SAP and more.
You can download it here: http://www.microsoft.com/downloads/details.aspx?FamilyId=4628FCA6-388D-45BC-A154-453B920DBCB8&displaylang=en
CRM and SharePoint Consultant