Hi,
Welcome to the forum. Your big problem with this image is that there's very very little contrast between the hair which is out of the depth-of-field and the background.
The normal photoshop method for cutting something out is to use masks and the magic wand tool, however, neither of these will be able to separate the hair from the bathroom wall easily. You'll probably find that it can be done pixel by pixel, but this is a recipe for losing your mind in frustration.
I started having a quick play with it in PS, and his hair is so fine that it's caused a halo effect echoing the background colours, so it's almost impossible to extract. You're probably going to have to try again with a different plain background I'd say. Plus the lighting sucked in the original, so there's no contrast.
You could try posting it in the Photoshop Challenge area, but I suspect you'd get much the same answer. It's going to be quicker, easier and better to take the shot again. Next time take the picture with a pleasing background and you won't need to cut him out!! :mrgreen:
Good luck & cute kid btw!
Rob