Sure, you could mess with Photoshop and its Background Eraser Tool to remove a background from a photo, but what if you don't own a copy of pricey Photoshop? I do own a copy of it but have never mastered it and don't like to use it. I don't even like waiting for it to load. For the Photoshop-less and Photoshop-averse, Web app Clipping Magic is worth a gander.
After navigating your way to Clipping Magic, you can simply drag and drop an image on the site or select a photo via the Choose File button. With your image loaded on Clipping Magic, you can now use the green and red brushes from the toolbar to tell the app which is the foreground you want to keep (green) and which is the background you want to remove (red). As you make brush strokes on the background, a yellow border moves to show you the line between foreground and background. For finer tweaks, you can shrink the size of the brush. There are also convenient undo and redo buttons, along with an eraser tool.
A preview pane on the right of your workspace shows you real-time results. You can select from seven background colors for your edited image or leave it transparent. When you are finished, click the Download button to download a copy of your photo. In the download window, there is a link to share a link to your photo (to avoid e-mailing a large file), but the link appears broken, acting the same as the Download Result button above it.
Clipping Magic is currently in alpha, so it's a little rough around the edges -- literally. I tested out the app with a handful of images and found that I could get a fairly sharp edge to my clipped foreground areas, but in each case, it was less than perfect. The app states that "hair and other partially transparent things such as veils or sheer clothes, are not currently handled." Professionals will obviously want to stick to Photoshop and the like, but for a quick clip of a photo, Clipping Magic may be of use.