GrandCentral still hasn’t given out invites and many are wondering if they ever will..  Fortunately it is still possible to get an invitiation to GrandCentral, but it won’t be easy.

http://invites.mashable.com/ is community for those looking for invites.  You sign up and can request invites for many different websites, including GrandCentral, since each users gets multiple signups to give away.

Currently there is a backlist, but to get a GrandCentral.com invite, I’m not sure of any other possibility.