What speed does the Arduino Duemilanove run normally?
16 megahertz
Do you have to watercool it? Can you use a very small heatsink?
arduino uses atmega 328 which it very tuny mcu when compared to the ones on pc no you need not provide it with any heatsink
Is the overclocking done in software? Or is it just a matter to switch out the crystal?
well just switch the crystal and then burn the appropriate bootloader
how do you removethe current crystal on-board?
DeSolder it
WELCOME 