The Enterprise Search Evaluation Guides for SharePoint 2010 product family are now available from the Microsoft Download Center now. 

Microsoft SharePoint Server 2010 Enterprise Search Evaluation Guide - describes the enterprise search features of SharePoint Server 2010 and familiarizes readers with how to implement enterprise search by using SharePoint Server 2010. This guide includes:

• Descriptions of the new and improved enterprise search features and technologies provided by SharePoint Server 2010.
• Details on the indexing and query architecture implemented by SharePoint Server 2010.
• Tours and walkthroughs of the main search features provided by SharePoint Server 2010.
  

Microsoft FAST Search Server 2010 for SharePoint Enterprise Search Evaluation Guide - describes the enterprise search features provided by FAST Search Server 2010 and is also designed to familiarize you with how to implement enterprise search by using FAST Search Server 2010 for SharePoint. This guide includes:

• Descriptions of the enterprise search features and technologies provided by FAST Search Server 2010 for SharePoint.
• Details of the additional features that FAST Search Server 2010 for SharePoint provides over and above SharePoint Server 2010.
• Details on the indexing and query architecture implemented by FAST Search Server 2010 for SharePoint.
• Tours and walkthroughs of the main search features provided by FAST Search Server 2010 for SharePoint.

The Search Technologies for SharePoint 2010 Products technical diagram compares the enterprise search capabilities in Microsoft SharePoint Foundation 2010, Microsoft Search Server 2010 and Microsoft Search Server Express 2010, Microsoft SharePoint Server 2010, and Microsoft FAST Search Server for SharePoint 2010.

Search Architectures for Microsoft SharePoint Server 2010 model describes the physical and logical architecture components of the search system