Sequiter OLE DB Consulting  
   Sequiter Software's Consultants can help you design, customize or optimize a custom OLE DB provider to access your data.
   http://www.sequiter.com/consulting/oledb/

HTMProvi  
   An OLE DB Provider for HTML tables. It reads, writes and creates HTML tables. HTMProvi supports the most important OLE DB interfaces, schemas and SQL commands. By T.K Software. [Commercial]
   http://www.htmprovi.com/

OLE DB Leveling: Choosing the Right Interfaces  
   Discusses the minimum provider interfaces that must be supported as well as the optional providers interfaces when developing an OLE DB provider. (Microsoft)
   http://www.microsoft.com/data/oledb/techinfo/oledbleveling2.htm

OLE DB for the ODBC Programmer  
   Presents an introduction to OLE DB programming aid ODBC programmers in understanding and using OLE DB. (Michael Pizzo and Jeff Cochran / Microsoft)
   http://www.microsoft.com/data/oledb/prodinfo/wpapers/oledb4odbc.htm

OpenAccess OLE DB SDK  
   Provides the toolkit and the run-time software components needed to implement an OLE DB provider for your data source. By Automation Technology, Inc.
   http://www.odbcsdk.com/products/openaccess/oledb_overview.asp

SimbaProvider for OLAP  
   An SDK and MDX Engine for developing OLE DB for OLAP (ODBO) providers to access proprietary OLAP data stores. It currently supports Win32 platforms. By Simba Technologies.
   http://www.simba.com/technologies/olap.htm

List of OLE DB Providers  
   Directory of authors and vendors of OLE DB provider software and OLE DB provider SDKs.
   http://www.sqlsummit.com/oledbVen.htm