I've made a tutorial on how to extract using the pen tool and a mask. I don't really extract much, but I prefer this method the most, because it's the most forgiving (if you made a mistake it's very easy to go back), and the pen tool gives you nice smooth curves :)
The program I use is Paint Shop Pro, but Photoshop or Gimp should have similar abilities (the functions are in different places that you'll have to find).
This assumes that you know how to use the pen tool/vector (If not, and if you use PSP like me, you can find my pen tool tutorial here).
If the image is too small, here's the link to the bigger image (I didn't want to make it too wide and mess up the forum layout)
Happy extracting!
