Idle queues in queue viewer
By default, in Exchange 2007, when you open the Queue Viewer, you will get a list of queues of your Hub Transport server. You should see a list of queues that are active at that time, or have been active in the past 3 minutes, since the Queue viewer will remove idle queues after 3 minutes. You can change this value however to any value between 5 seconds and 1 hour, as can be seen in the example below.
[PS] C:\>Get-TransportServer DC | Set-TransportServer -QueueMaxIdleTime 00:00:05