These spiffy little devices attach to your camera via tripod mount, and have three legs just like a tripod. The difference? These legs are flexible, able to wrap around or stand up on virtually any surface. Around a tree branch, on a streetlight, there are thousands of vertical and horizontal surfaces surrounding you everyday that are perfect for gorillapods to wrap their flexible legs around.
As with the beanpod, the gorillapod cannot elevate the camera very far above the ground: you need a surface to which to attach it. So, if you're planning on heading out into the desert, then maybe this isn't the best idea.
Oversized cameras with large attachments like telescoping lenses might not be able to really take advantage of a gorillapod, just due to sheer weight and size issues. Heavy duty gorillapods are advertised to work for up to 6 pounds, but that's stretching it. However, for anything under the size of your basic DSLR, it's a great choice, and one that can fit right in your pocket.
Also, some photographers have difficulty adjusting the gorillapod to exactly match the angle at which they want to shoot, especially with heavier cameras.
Joby is an excellent manufacturer of Gorillapods, and may be purchased for up to 50$. Gorillapods are also very easy to make for yourself.