also useful on hot summer days, produces a nice and cool climate in your room...
they used 3DMark for the benchmarking:
http://www.futuremark.com/
I am not really a friend of overclocking (at least not on my systems), I will even underclock my new system...I am a silence freak...
if your mainboard supports it depends on the BIOS version used by the manufacturer and from the CPU, a BIOS update doesn't necessarily enable overclocking features. upgrading BIOS can not be done from the system HDD because you need to boot the firmware updater which does the job on a lower level than the OS one, it can be done via floppy, CD or USB (if booting from USB is supported).
using the latest firmware is generally a good practice because it fixes bugs and can make your system more stable.....the mainboard BIOS is not the only firmware in your system than can be upgraded, a while ago I upgraded the firmware of my DVD drives for example.
but back to overclocking:
to be honest I don't recommend it until you haven't done all possible system optimizations, on hardware- and on software-level...overclocking always reduces the lifetime of the system and/or increases the noise level.