I've been playing around with gel transfers for the past few days. I actually posted a class on this on the Life Preservers message board. I love the effect, although it takes a little practice to perfect. You can find the complete class and directions
here. Here are a few of my examples.
Here is an ATC I did using a transfer made from a picture from a magazine.

This card was made using a transfer of a vintage clip art image from the internet.

Her are a few of my early attempts. I love the artsy distressed look of these images.