The Microsoft Dynamics CRM Solution Accelerator for Siebel provides an opportunity to partners to quickly demonstrate integration between Dynamics CRM and Siebel during selling situation. They can also customize and extend this solution to meet production time requirements of the customer organization. Customization guidelines, sample code, maps and schemas for doing this are provided here. Demo kit uses BizTalk Server 2006 and it is scalable.
http://code.msdn.microsoft.com/Project/Download/FileDownload.aspx?ProjectName=CRMMicrosoftDynamic3&DownloadId=557
