The store is at prentfection.com and the link is Designs by Jake. This is a print on demand store, they take care of all of the details :).
Here is a sample of what is available:
All sorts of colors and sizes are available.
NEW: Available with Jake's "Pawtograph!"
Have a favorite Jake picture you'd like on a shirt or other item? Drop Jake a line at firstname.lastname@example.org and discuss it with him!
A small portion of the selling price goes to Jake to help with his surgery!