How to record Intercom / ATC in a small aircraft like a Piper Archer? For making videos it would be nice to have some more sound than the engine sound recorded by my GoPro. What ideas do you have to record the aircraft intercom? It won't be a problem for me to have two files (an audio and a video file).

Edit: I'm looking for a good sound quality comparable with that which you will have while sitting in the aircraft listening to the intercom.
For the GoPro specifically there are audio recording cables you can buy which connect to your intercom jack and provide a pass-thru connection for your headset.
There are other cable options available to support recording on different devices (e.g. iPhone/Android phones and tablets).

As is often the case with "aviation" accessories these can be somewhat expensive, but they're also pretty reliable drop-in solutions. As mah noted if you have a spare headset jack you're not using plugging into that can be much cheaper and just as effective.