The Tibetan Buddhist say that by sleeping with your head pointing north you will remember more dreams. By sleeping with your head pointing south your sleep will be much deeper and more refreshing.Sleepy yin yang
Though out history reference is made to magnets to ease pain and reduce swelling. Today we know the North pole of a magnet increases blood oxygen levels while the south pole reduces them.
So I had a look around what teh different skools had to say about it. More oxygen can be easily equated with more dreams just like less oxygen can be equated with deep sleep.
If there is any difference at all then that should be it.
In my not so very humble opinion (mah lets call it my arrogance) it gives us a revolutionary way of sleeping.
If you are physically exhausted then sleeping towards the south is a good idea. If you are mentally exhausted then sleeping towards the north will give you that small bit of extra dreams you need to decipher and catalog the data of the day. Students should sleep north while athletes should sleep south. If you have a sore foot or a sore hand just point that towards the north. Don't expect miracles, it wont cure you or anything. But I imagine the effect over time could be quite big. Missing out on a single thought could potentially remove important conclusions. Do that a few times and life could be vastly different.