Hmm there are a couple of ways. I personally use the polygon lasso tool, sure it takes ages but it is very accurate if you put the time in. Simply select the area then hold down Alt to deselect unwanted pieces of the background and to fine tune the image to get the perfect edges.
Another way is to use Filter-->Extract (or Alt+Ctrl+X ) which is kinda like quick mask, pretty easy really, just "paint" over the area u want to extract, right click the areas you dont want (ie. background?), you should end up with a selection, then its just a case of copy and paste into a new document, or inverse selection (Select->Inverse or Shift+Ctrl+I) and press delete.
If this doesnt help or its not what your after, let me know and I'll try something else
