A quick way to create a clipping path in Photoshop on an image is to use the Magic Wand tool and Make Work Path feature.
This trick works best if the image has a clean background and edges.
- Choose the Magic Wand from the Toolbox
- Click on the background of the image
- Go to the Path palette
- Choose Make Work Path from the menu
- Set the Tolerance at 0.5
- After the path is created, re-save the Work Path under a new name