No double, you can easily take photos with your iPhone 4 or 4S. But if you want to shoot steadily or take self portraits, the following Tilt Mobile keychain tripod should be able to meet your requirements.
Tilt Mobile is a practical, ultra portable ball head tripod designed for iPhone 4 and iPhone 4S. As we can see from the images, the tripod features keychain-sized, go-anywhere design, and comes with a grippy base in order to hold tightly on rough or smooth surface, while the iPhone-safe magnetic ball head mount allows you to smoothly adjust the position of your iPhone at just about any angle for perfect group and self-portrait shots, and the portable tripod supports both portrait and landscape modes. Apart from that, the custom opening lets you attach the tripod to your keychain.
Tilt Mobile keychain tripod is priced at $15 USD. If you’re interested, jump to Photojojo for more details.
Additionally, if you need other options, you might like to check Gerber tripod multi-tool and more via “tripod” tag.