As you might be aware, there is a BizTalk Adaptor for Microsoft CRM 3. I havn’t spoken to anyone who has tried it but I just found a nice blog that describes a lot about how to set it up. It is focused for BizTalk experts, but can be very helpful to get a BizTalk CRM integration project started. Have a look and judge for your self:
http://blogs.msdn.com/brajens/archive/2007/05/27/using-microsoft-biztalk-dynamics-crm-adapter-part-1.aspx

Gustaf Westerlund
CRM and SharePoint Consultant

Humandata AB
www.humandata.se