Oops, I think this is a little better:

[font="Courier New"]SELECT

   DB_NAME() AS database_name,

   MP.name AS database_user,

   RP.name AS database_role,

   SP.name AS server_login,

   SPR.name AS server_role

FROM

   sys.database_principals MP LEFT JOIN

   sys.database_role_members R ON

       MP.principal_id = R.member_principal_id LEFT JOIN

   sys.database_principals RP ON

       R.role_principal_id = RP.principal_id LEFT JOIN

   sys.server_principals SP ON

       MP.sid = SP.sid LEFT JOIN

   sys.server_role_members SRM ON

       SP.principal_id = SRM.member_principal_id LEFT JOIN

   sys.server_principals SPR ON

       SRM.role_principal_id = SPR.principal_id[/font]