Another method for 3D viewing is called cross-viewing or the cross-eyed method. You aim your eyes so that the lines of sight of your eyes cross in front of the image. When you cross-view, the muscles inside your eye that control the focusing lens contract strongly and shorten.
Instuctions:
1.Grab a pencil-pen and hold it at eye level.
2.Look the pencil-pen.
3.Bring the pencil-pen ever closer to you.
(IMPORTANT) The pencil-pen should remain at the level of your eyes!
4.If you have properly followed the instructions all around you will see cloudy.
5.Try now and without the pencil.
Like this:
now test it here
http://www.flickr.com/photos/lordv/73174852/in/set-1571779/lightbox/
Instuctions:
1.Grab a pencil-pen and hold it at eye level.
2.Look the pencil-pen.
3.Bring the pencil-pen ever closer to you.
(IMPORTANT) The pencil-pen should remain at the level of your eyes!
4.If you have properly followed the instructions all around you will see cloudy.
5.Try now and without the pencil.
Like this:

now test it here
http://www.flickr.com/photos/lordv/73174852/in/set-1571779/lightbox/