The iPhone makes a great at-the-ready camera. Those of us appropriately sidearmed with an iPhone usually keep it easy to grab, which makes it the perfect device to yank from our pocket and snap a few pictures. And while the digital zoom is an awesome feature, it has limitations, and usually ends up killing the final photo quality. So, you're stuck with the convenience of your iPhone versus its inevitable limitations as a camera.
Photojojo has a solution. The iPhone Telephoto Lens screws onto an included iPhone case, allowing you to get up to 8x the normal amount of zoom. The lens fits in your pocket when you're not using it, so it's not like you're hauling around a huge accessory to go with your iPhone. Even better, the iPhone Telephoto Lens comes with a tripod. As most professional photographers will tell you, using a tripod is the single best way to improve your photographs.
The lens package is available for both the iPhone 3/3GS and iPhone 4. For US$35, you get the lens, a case and a tripod. It's a pretty good deal to help improve your iPhone pictures.