I've just been installing the new Kubuntu KDE4 Remix Beta on an old Acer L100 Media Centre using the Alternative Install CD (so I can do a text mode install) as I only have an old CRT TV attached to it. When I tried to boot from the CD it looked like the installer picked a display mode that didn't work with the TV as the picture lost stability and was unviewable. I couldn't find the usual options to change the screen mode, but found that this worked to override the screen mode:

• At the menu for installation press F6
• You will now see a long line of text that tells the Linux kernel on the CD how to boot
• Delete "quiet - -" from the end of the line
• Enter vga=789 to force boot into 800x600 mode
• Press enter to boo, the screen will blank for a few seconds, after that you will see the text installer 

You can find a listing of the Linux VGA modes at: http://en.wikipedia.org/wiki/VESA_BIOS_Extensions#Linux_video_mode_numbers