My Dell 600m runs hot. Really hot. Even in XP. I now have a permanent shadow on my screen, which rather ticks me off.

I've installed FnFx, but it doesn't seem to make much difference, if it's working at all. I don't HEAR my fan going. So.

Either 1) can I change the BIOS to switch on the fans at a lower temp? or
2) does anyone have a notebook cooler that works with Linux? I can find Mac or WinXP compatible ones, but no word on Linux.

Poor laptop! I didn't mean to burn you! God, I wonder what a replacement screen will cost me. Gah.

Are you sure you couldn't "force" the fan on in linux? Take a look at /proc/ACPI/FAN/../
If you see a files named "status" or "info", it means Linux at least see your fan. But sometime the BIOS have the control over the fan and sometime, the BIOS is dumb.
Sometime in these files, you have a "force_on" option, mean you could force the fan to be always running. Also, as you have a dell I know you can load some additionnal drivers that could, maybe, allow you to control the fans The module is called "i8k" I believe, but you have to force the loading if you don't have an inspiron 8000. It's at your own risk but if you want to try, the command should be like "modprobe i8k force=1" .

Depending what ACPI feature your laptop support, you could also throttle down the CPU speed (use less power so less heat?).
Also, consider instaling "i2c" (probably already in your kernel) and "lm_sensors", as it would allow you to know the temperature of your laptop... Maybe it's not that bad. (Below 60 degrees is acceptable atmo)

/proc/ACPI/fan/ is empty.

Isn't i8k for Windoze? I'll look into it...

Google with "Cpu Frequency Scaling", "powernowd", "cpudynd" and "cpufreqd". With CFS you can (with most modern processors) control the processor's clockrate - usually lowering it when there is nothing happening. This will reduce heat and power consumption.

With some system almost the same thing can be achieved with "ACPI Throttling".

I forked over the $25 for a nice little notebook cooler. It's pretty neat! Vantec LatopCool2. Nice, thin, blue, two fans with adjustable speed, works with power from your laptop via USB2, no problems whatsoever. Much better value than the Targus cooler that was also on display (for $20 more).

Hope that helped someone else.