Tilt-shift photography is a technique that requires a special lens to change both the perspective and focal field of an image. A similar effect can be created in PhotoShop and other high-end image editing programs, but it's a lengthy effort that casual photographers will probably find daunting. Web-based photo editor Tiltshiftmaker has automated most of this process, letting you achieve a similar effect right in your browser.
To do it yourself you can either upload a photo from your computer, or drop in the URL of one hosted online. From there you can adjust how much of the shot you want in focus. This is done by dragging a horizontal bar up and down the shot, the size of which can be increased or decreased to bring more of your picture into focus. There's also the option to blow out the saturation to make your shot look cartoonishly colorful.
The test shot I used of the street outside CNET's office turned out great (see it below), and only took a few seconds to put together. My only qualm is that the editor's preview, which needs to be refreshed between each edit to see changes, is a little bit small, making minute adjustments on larger photos a tad difficult.