I have last year's MBP with OS X v10.5.6 with the 27 pin DVI connection on the right side.
This is loaded with FCP Suite Academic version.
I have a Marshall HD LCD Monitor which takes DVI-D or DVI-I.
System Preferences/Display on the Mac show the display icon in my menu and my Mac changes resolution when booted up with the DVI-D cable connected to a powered Monitor. So I think the Mac knows something is there.
The monitor does not see any video from the Mac in any resolution.
It is supposed to display input resolutions from 640x480/60Hz, all the way up to 1024x768.
All I get on the monitor is a no signal warning.