[Techtalk] Switching resolutions when I switch to an external monitor

[Mary]

Hi all,

My laptop is running Ubuntu 5.10 (Breezy Badger). It is a Fujitsu S6120
Lifebook. I quite often hook it up to an external monitor when I'm at a desk
and would like it to switch resolutions when I press the "switch to external"
function key rather than doing what it currently does, which is simply take the
settings for the laptop screen and use them for the external monitor.

The settings for the laptop monitor are 1024x768, 60Hz. This is what
"get-edid | parse-edid" tells me about the external monitor:

Section "Monitor"
        # Block type: 2:0 3:fc
        Identifier "Direction L7ADIR"
        VendorName "DIR"
        ModelName "Direction L7ADIR"
        # Block type: 2:0 3:fc
        # Block type: 2:0 3:fc
        # Block type: 2:0 3:ff
        # DPMS capabilities: Active off:yes  Suspend:yes  Standby:yes

        Mode    "1280x1024"     # vfreq 75.025Hz, hfreq 79.976kHz
                DotClock        135.000000
                HTimings        1280 1296 1440 1688
                VTimings        1024 1025 1028 1066
                Flags   "+HSync" "+VSync"
        EndMode
        # Block type: 2:0 3:fc
        # Block type: 2:0 3:fc
        # Block type: 2:0 3:ff
EndSection

Here's what lspci tells me about the video card:
0000:00:02.1 Display controller: Intel Corp. 82852/855GM Integrated Graphics Device (rev 02)

What can I change in my X settings so that it switches to appropriate
resolutions when switched to an external monitor?

-Mary