Someone has written a little web application that Holganizes photos. It crops to square, adds a border and light leaks and can, if you want, convert to black and white. Not bad. My only complaint is that it shrinks the image to 300 x 300 pixels, which is kind of small.
For more examples, go look at their gallery page.
(Photo: The Metamora Aqueduct, Holganized; original image here)
red paper boat 