In earlier versions of Exchange Server the Message Tracking log settings were configured through the GUI interface.  Now with Exchange Server 2007 you can set the Message Tracking log path in the GUI, but you need to hit the Exchange Management Shell for other settings such as the log retention period.

To view the retention period on all of your Hub Transport servers you can use the Get-TransportServer cmdlet.

[PS] C:\>Get-TransportServer | fl name, messagetrackinglogmaxage, messagetrackin
glogpath

Name                     : SERVER1
MessageTrackingLogMaxAge : 30.00:00:00
MessageTrackingLogPath   : C:\Program Files\Microsoft\Exchange Server\Transport
                           Roles\Logs\MessageTracking

Name                     : SERVER2
MessageTrackingLogMaxAge : 30.00:00:00
MessageTrackingLogPath   : C:\Program Files\Microsoft\Exchange Server\Transport
                           Roles\Logs\MessageTracking

The MessageTrackingLogMaxAge attribute is in the format dd.hh:mm:ss (d = days, h = hours, m = minutes, s = seconds). To modify all of your Hub Transport servers to retain Message Tracking logs for 60 days you can pipe the Get-TransportServer cmdlet to the Set-TransportServer cmdlet.

[PS] C:\>Get-TransportServer | Set-TransportServer -MessageTrackingLogMaxAge 60.00:
00:00

Get-TransportServer will now reflect the new setting.

[PS] C:\>Get-TransportServer | fl name, messagetrackinglogmaxage, messagetrackin
glogpath

Name                     : SERVER1
MessageTrackingLogMaxAge : 60.00:00:00
MessageTrackingLogPath   : C:\Program Files\Microsoft\Exchange Server\Transport
                           Roles\Logs\MessageTracking

Name                     : SERVER2
MessageTrackingLogMaxAge : 60.00:00:00
MessageTrackingLogPath   : C:\Program Files\Microsoft\Exchange Server\Transport
                           Roles\Logs\MessageTracking