(First of all, I thank Drew for introducing the lenticular kit to me ^_^)
Lenticular lens is an array of very thin magnifying glass like the ones in the 3D postcards you see in souvenir shops. I recently learned that you can purchase lens kits online and create your own 3D photos. Here is the gist of what you have to do:
At Stonehenge for the image above, I took 4 pictures, each after taking a few steps along the pathway surrounding the monument. At Grand Teton, I took pictures of the mountains every few seconds from the car (driven by my wife) going along the mountain range. Also, I once asked someone to sit in an office char and rotate. Moving his feet sideways by half a foot after each shot seems to have yielded the best result. Make sure you don't tilt the camera between the shots. That would add unnecessary steps when aligning the images.
After taking the photos, align all the images
A program called "SuperFlip!" can be downloaded from the VueThru.com website. It does come with a detailed help file (C:\Program Files\Flip!\Flip.hlp). But there are many parameters to set up.
This magnified picture shows how the images are interlaced:
Again, the lines-per-inch count depends on the printer and the paper you use. Non-glossy paper tends to shrink. A fractional difference could decrease the 3D effect by creating discontinuity in the image.
Place the printed interlaced image and the lenticular lens on a flat surface. Align the image and the lens perfectly in parallel. Then slide the lens sideways (by 1/40 or 1/60 inch at a time ;) ) and see the effect. I attached a plastic ruler on my desk with a double-sided tape and used it as a guide &dash I moved the lens like on a rail.
This is the most unnerving part since ruining a $5 lens is not fun. The kit comes with the detailed instructions titled "Lamination".