EXEC sp_addlinkedserver   
   @server='TestServer', 
   @srvproduct='',
   @provider='SQLNCLI', 
   @datasrc='YourServer\InstanceName'

EXEC sp_addlinkedsrvlogin 'TestServer', 'false', 'sa', 'sa', 'password'

select * from TestServer.master.dbo.sysobjects