I'm wanting to do various videos when I get my iMac but have no idea how I'll actually be able to connect the microphone or headsets since the iMac has only one jack. I'm new to the audio/video scene and I have no idea - I've looked around but couldn't find much. I'd like to record using a good standalone microphone as well as a good set of headphones. How would I go about doing this with a single jack on the iMac? Cheers.