MOSS: Report of Users and their permissions

-- All users in site collection

Select tp_Title,tp_Login, tp_IsActive from UserInfo order by tp_Title,tp_Login, tp_IsActive


-- All users in a group

Select Distinct Title, tp_Title,tp_Login from Groups gr

inner join GroupMembership grm on gr.ID = grm.GroupID

inner join UserInfo usr on usr.tp_ID = grm.MemberId

order by Title,tp_Title,tp_Login




-- All groups for a user

Select Distinct tp_Title,tp_Login, Title from Groups gr

inner join GroupMembership grm on gr.ID = grm.GroupID

inner join UserInfo usr on usr.tp_ID = grm.MemberId

order by tp_Title,tp_Login,Title


Thanks to my mate Navneet Singh.