try this...

select srv.name,lgn.Remote_name

from sys.servers srv, sys.linked_logins lgn

where srv.server_id=lgn.server_id

and lgn.remote_name='login1'

also refer to the BOL link

ms-help://MS.SQLCC.v9/MS.SQLSVR.v9.en/tsqlref9/html/06d53a67-7804-4f1f-8201-3e42dc48ba79.htm