Lion: getting notifications when a space changes?

In Lion, is there any way within an ASOC application to receive some sort of notification when a space is changed?

In other words, if I go into Mission Control and select a new space, or if I select an application that is open in a different space, is there a way my running ASOC application can receive a notification that the current space has changed?

Thanks in advance for any suggestions or pointers to docs.

You want NSWorkspaceActiveSpaceDidChangeNotification. See NSWorkspace.

Thank you!