Using Clipping Magic you can instantly remove any complex background easily. Its a web based service and completely free. This is how it works:
You go to http://clippingmagic.com
Drag and Drop your Image to the Box
The uploaded image and its preview will load. From top use the red and green tool to mark which portion you want and which portion you dont. Default brush size is 30px, but for detail selection, choose 10px. Also dont forget to zoom in. You can always undo if you think you made a mistake. You can apply green on red or vice versa if you need to.
As you draw, you can see the result almost in real time on the right side. Once you have done the basic parts, click on Refine from top and select Manual, choose Smooth value say 4 or 5. You may also choose to blur your edges for smoothness. Offsetting the boundary can also be a good trick to gain better result.
Once you’re happy with result you can click on Download to get the file as PNG.
I did a real quick job (without bothering too much for perfection) in just 2 to 3 minutes for the following image using Clipping Magic.