Ubuntu - change available screen resolutions

[RobG <rgqld@iinet.net.au>]

Hi, I have installed Ubuntu using VMWare Fusion beta on Mac OS X.
During installation, I accidentally didn't include the correct screen
resolutions and so only have the default 1024x786 and smaller. I have
a MacBook and also use an external monitor, so I need to include
1280x1024 (external monitor) and 1280x800 (MacBook screen) in the
available set of resolutions.

How can I change the list of screen resolutions available in System ->
Preferences -> Screen resolution?

Also, please let me know if this is the appropriate place to ask such
questions.

--
Rob