might want to wrap this in sp_msforeachdb and strip out some of the stuff you dont need
select * from sys.database_role_members drm
join sys.database_principals dp
ON drm.role_principal_id = dp.principal_id
join
sys.database_principals dp2
on
drm.member_principal_id = dp2.principal_id
where dp.type = 'R'
and dp2.type_desc like '%user%'