Just rebuilt my Vista machine with an RC1 version of Vista SP1 and got caught by this one.
In both Vista SP1 and Windows Server 2008, the Remote Desktop Program has been updated to version 6.1 (6.0.6001) and one of the changes is that the functionality previously associated with the /console switch is now called the /admin switch. Wasted a few hours chasing this one down. We use a lot of remote desktop connectivity with virtualization so more than a handful of people are going to get caught.
If you use "mstsc /v:servername /console" in a script file then the /console will be ignored (with no warning) and you will be connected to a normal session that is not the server console. If you specify the /console switch in the RDC GUI connection dialog then it will tell you "an unknown parameter was specified in the computer name field".
All is good if you use /admin instead of /console. It would have been great if the developers had seen fit to at least detect the /console switch and issue a message along the lines of "/console no longer supported, use /admin instead" but I guess that's why blogs exist.
Anyway, there is a detailed discussion on the rationale behind the change here: