Here is a great guide on different ways you can fold and flag your hanky. Just pretend it's someone's back pocket instead of a jacket... Have fun with the different parts that are visible and hidden depending on how your hanky is folded.
One Point Pocket Square Fold
Lay your pocket square flat with one corner facing up and one corner facing down.
Fold the bottom corner up to meet the top corner.
Fold the left corner to the right.
Repeat and fold the right corner in to the left.
Two Point Pocket Square Fold
Lay your pocket square flat with one corner facing up and one corner facing down.
Fold the bottom corner up and just to the left of the top corner.
Fold the left side in towards the right.
Fold the right side in towards the left.
Three Point Pocket Square Fold
Lay your pocket square flat with one corner facing up and one corner facing down.
Fold the bottom corner up to the top just to the left of the top corner.
Fold the left side towards the right, and up to the right of the "middle peak".
Fold the right side straight across in to the left.
Four Point Pocket Square Fold
Lay your pocket square flat with one corner facing up and one corner facing down.
Fold the bottom corner up to the top just to the left of the top corner.
Fold the right side towards the left, and up to the left of the "second peak".
Flat Pocket Square Fold
Lay your pocket square flat with the two top corners horizontal.
There are a number of variations of the flat fold with names like the "TV Fold", the "Architect" or the "Presidential".
Fold the the left side over the right side.
Fold the bottom up just short of the top.
Four Point Crown Pocket Square Fold
Lay your pocket square flat with one corner facing up and one corner facing down.
Fold the bottom corner up to meet the top corner.
Fold the bottom corner up to the top just to the left of the top corner.
Fold the left side towards the right, and up to the right of the middle point of the crown.
Turn the pocket square around and adjust the points of the crown.
Rolled Puff Pocket Square Fold
Lay your pocket square flat with the two top corners horizontal.Pinch the middle of the pocket square and pick it up.
As you pick up the pocket square tuck the sides in as in the diagram.
With one hand firmly holding the pocket square, use your other hand to gently gather it closed.
Now gracefully roll the top of the pocket square in the direction of the arrow.
Carefully lift the bottom points up.
Firmly grasp the bottom of the pocket square.
One Point Roll Pocket Square Fold
Follow the instructions for a "Rolled Puff Pocket Square" above.
Now for a bit of flair extend one point.
If the extended point points towards the shoulder that would tend to broaden the shoulders.
(In the illustration to the left the point is going towards the right which works well for gentlemen who have large shoulders)
Double Point Roll Pocket Square Fold
Follow the instructions for a "Rolled Puff Pocket Square" above.
Now extend out the two end points and you are done.
Four Mountains Pocket Square Fold
Follow the instructions for a "Rolled Puff Pocket Square" above.
Turn your pocket square upside down instead of lifting bottom points.
Dunaway Pocket Square Fold
Follow the instructions for a "Rolled Puff Pocket Square" above.
Flatten the points and turn around so roll is in front.
Three Stairs Pocket Square Fold
Lay your pocket square flat with one corner facing up and one corner facing down.
Fold the bottom corner up to meet the top corner.
Fold the front fold partially down so that it goes past the bottom of the pocket square.
Now take the same fold and fold it back up towards the top of the pocket square.
Now fold back towards the bottom of the pocket square. Be sure and keep your folds neat.
Fold a small fold towards the top of the pocket square. Gently press with an iron.
Flip over the pocket square.
Fold the right half of the pocket square behind the left side.
Rotate the righthand corner of the pocket square 90 degrees. Fold the left side to the right.
Fold the right side to the left and we are done.
Winged Puff Pocket Square Fold
Lay your pocket square flat with one corner facing up and one corner facing down.
Fold the bottom corner up to meet the top corner.
Fold the top left and right corners down and in.
Fold the left, right and bottom corners in.
I found this great guide on this site: http://blogs.myspace.com/index.cfm?fuseaction=blog.view&friendID=195293647&blogID=416187225
