Can't even get 2D Working beyond 640x480

[Brian Grant]

Newb and can't get my screen out of 640x480 land with a 60hz refresh.  
Everytime I switch the monitor to a mere 800x600 it can't start X.  
And an endless cycle of "cant start X reverting to text" begins. In  
the terminal I'm not too sure how to edit my XFF86config file w/o  
screwing it up. I cannot get around vi or perl... most unix editors  
actually. I have a dual 1Ghz quicksilver with a Radeon 9800 Pro. I  
know that my card can go as high as 2048x1536 on OS X. And I would  
like to run Yellow Dog at least @1280x960. I am Using a standard 19"  
SyncMaster CRT.
So is it a driver I am lacking? Where do I get it? Do I just edit my  
profile w/ Xconfigurator and it will see it? I don't know. If all you  
need to do is edit an already embedded driver then how do you do it?
Most help forums tell people to edit the config file. Thanks.  How do  
I do that w/o knowing the various commands of the unix editors vi,  
perl, pico, etc. I was unable to find a step by step ecept this one
http://www.yellowdoglinux.com/support/solutions/ydl_3.0/ 
video_config.shtml
Tried it and did not work. Anything you people could help with would  
be appreciated. What better place than with people who feel your pain.
Let me know if my request is even possible. Most places tell me that  
ATI drivers don't work at all for any card w/ PPC Linux. I need a  
little direction. Thanks again.
Brian