Writing a Custom Claims Provider

Below are the links to a 4-part series which demonstrates how to create a Custom Claims Provider by implementing the necessary properties and methods to support various Claims-based scenarios:

http://blogs.technet.com/b/speschka/archive/2010/03/13/writing-a-custom-claims-provider-for-sharepoint-2010-part-1.aspx

http://blogs.technet.com/b/speschka/archive/2010/03/13/writing-a-custom-claims-provider-for-sharepoint-2010-part-2.aspx

http://blogs.technet.com/b/speschka/archive/2010/03/13/writing-a-custom-claims-provider-for-sharepoint-2010-part-3-searching-claims.aspx

http://blogs.technet.com/b/speschka/archive/2010/03/13/writing-a-custom-claims-provider-for-sharepoint-2010-part-4-supporting-resolve-name.aspx

The 4-part series has also been published as an MSDN Article here:

http://msdn.microsoft.com/en-us/library/ff699494.aspx