Is this for the power button, or something else?
If it's for the power button, sure, it will work fine; I've actually used those very switches as power buttons for PC motherboards before; they work great (if overkill.) The motherboard header just has two pins for the switch itself and two for the LED; you just connect these to the corresponding pins on the switch.
Some low-power motherboards (Atom) I've worked with assume a red or green LED for the power indicator. I used one of the Bulgin switches with a blue LED indicator and it's a bit dim (the forward voltage of blue LEDs is a little higher than red or green, which changes the resistor value you need for a given current.) So, if you use blue or white, it might be a bit dim, depending on your motherboard (I've gotten pretty good brightness with blue LEDs on standard desktop boards, though.)
You'll probably want some 100-mil 2-position sockets to actually plug in properly to the headers on the motherboard.
If you want to wire up a button for something other than power or reset, then those buttons will still work, but you'd need some way to actually interface it to the PC (such as through the parallel port or via a USB interface.) Or, some USB DAC chips (such as the BB PCM270x chips) have a few extra pins for wiring up play/pause/skip/volume buttons, which appear on the PC side as a USB HID device.
