As for the speed switching, I'm not sure if linux currently supports this ( at least not in the 2.4.x series ).. As for the fan, my laptops fan switches on and off automatically, without acpi.. Maybe check your bios to see if you can enable APM and use that instaed of ACPI. Also, it would be very strage if your hardware didn't control the fan automatically, and relied on the OS to do this.. What would happen if Windows crashd and didn't start the fan up?