I recently started this myself and I am controlling it with my Touch. You should start out with a monitor to set up screen sharing so that you can pull up the Mini screen on your iMac and this will allow you to move folders, apply updates, etc. which you cannot due with the Touch.
When you add the Touch as a remote you will also need to share the screen on your iMac as you will need to put in a code in iTunes to allow for the Touch to take control.
I have found the lack of monitor not to be a problem as I control everything from my MacBook Pro from the listening chair or my Touch.