Great series of article here !!

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

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

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

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

Part 2 of my previous article next week….