My first attempt

I read the guide on how to use the background eraser and it seemed to do the job. Does anyone have any good tips on making it come out cleaner?

 

The hair actually looks fairly clean. You can see that some strands are pixelated, and so is the shirt underneath the arm. Overall - looks good. Just a few adjustments to smooth out those edges, and you have yourself a good render.

I'd also crop out the really shadowed part near the left arm, or blend it in with the work you're applying it to.

 

Where can I find the program for this? I'd love to try it on some things.