Had to get a second headset and opting for a cheap model, mistakingly got one with analogue in- and output. The microphone didn't work and only after a long time - and taking back the headset to the shop to get it replaced - did I find out newer MacBooks and PowerBooks don't have a built in microphone amplifier :(
So if you don't want to build your own amp, stick to a USB headset for your Macbook.

Warning: banal content! Apple's remote control that comes with all new Macs was fun to fiddle with ONCE. Then it lay there getting ever more dusty. Working at my desk today i listened to iTunes on shuffle mode and often I'd move my cursor to the iTunes Dock icon, pause a little and select "next" to skip to a better song. It just seemed like too much effort, too much distraction from work. So I tried the remote, wondering if it works without the Front Row app running - and it does! And it reacts instantly. So the next track is now one push of the button away. Nice! Now PLEASE get back to work ;)