Hearing/sensing Apparitions, How does one come about this? Options

I've heard of others being able to "sense" apparitions such as ghosts and even hear the chatter of the other side, yet not being able to see them. Though this came about to them through natural born capability, how does someone achieve the sensing and hearing of other spirits or entities?

Here's some random info I picked up in a random place:

According to a 70s telepathy pseudomanual (eh, about 75% of it was fluff), if you concentrate on training your ears enough you will be able to 'tune in' to others' thoughts. To do this it is recommended you relax in a quiet room and try to notice all perceptible sounds. Closing your eyes helps focus, as it gets rid of distracting visual clutter. Practice hearing everything; eventually you'll start noticing 'subsounds.' I don't know about the telepathy part (well, actually I do somewhat but I don't want to get into that (IMG:style_emoticons/default/happy.gif)), but doing this exercise does increase your overall awareness, to the point that you might be able to 'hear' other vibrations you normally wouldn't (i.e. spirits).

As mentioned above, meditation helps.