ppc - problem with LCD screen resolution

[Robert Fernandes]

Hi - just installed ubuntu on my G4. I have a 17" Apple LCD Studio 
Monitor. When I boot the system, all I get is a tiny GUI in the middle 
of my screen. I looked at the XF86Config and it says it is using a 
default depth of 24 with a resolution of 1272X1017. I tried changing 
that to 1280X1024 but no change. Under System, I choose to set my 
screen resolution but the only choice available is 640X480. Can anyone 
help here?

-Bob