you can always download AUDACITY from download.com for free, it's a small file so you can use it's stereo mix feature.
This feature allows you to record ANY sounds that are coming from your speakers,
so if you watch a video that has binaural beats in the audio you can record and save it,
or for anything really (like listening to a song on YouTube and recording the audio).
This is what i did to get Binaural Beats from a video on youtube, just click record on audacity before you press play so any sounds that are played will be recorded, then "export" the wav file. Once it's done exporting it should be on your desktop and you can put it on your ipod or whatever.