Yep, it's still there.
Don't know how long for but M$ appear to have removed the link from the cd, and to new players, but left it on the Zones' servers for the old sob's (like me).
Providing you have the direct link:-
http://zone.msn.com/en/route/flightsimulator/,
you can still get into Ridgerunners by signing in and visiting this page. *Once your Zone Friends list has come up, refresh the page and you will see the 'hidden' rooms as always.
Same with CFS2's Midway.
*You can refresh before your ZF comes up but I find this then prevents ZF coming up altogether.