All incorrect.... :p
First, make sure your image is a layer, and not a background.
Go to Image > Extract
Zoom in a bit on the picture.
Select a brush size that will let you easily trace the image that you want to keep. (Smaller the brush the better)
Trace the image as best as possible.
Use the paint bucket tool to click inside the outline you just made.
Then use the the eraser tool and the history brush to touch up some of the jagged edges.