should you be so unlucky to have to use a box with onboard Intel "Graphics", specifically a 965Q chipset, and also one of those fat Dell screens which suck at all resolutions but 1680x1050, and maybe even want to run debian Etch (without testing or experimental or somesuch), then you'll hate all the involved hardware manufacturers. (Likely you do that anyway, for unrelated crimes against syadmins but regardless: THIS time i did find a way to coerce them to function.)

apt-get 915resolution and the usual xserver-xorg-video-i810. By itself that doesn't work and leads to all kinds of weird behaviour on behalf of the stupid monitor. However, with the following two mods things suddently DTRT:

• make sure 915resolution runs with parameters for both htotal and vtotal. the default install doesn't allow you to specify these in /etc/default/9154resolution, so you'll need to hack up the init script. the one and only set of parameters that worked for me are mode 3a, xres 1680, yres 1050, bits 16, htotal 2240, vtotal 1089. i couldn't get it to work without the extra htotal and vtotal settings.
• add the following modeline to your /etc/X11/xorg.conf:

  Modeline "1680x1050" 146.2 1680 1784 1960 2240 1050 1053 1059 1089

  none other worked for me; apparently the htotal and vtotal values are super-critical.

et voila: widescreen.