Do you want to know how it's done? Learn how to use Photoshop the easy way!
Hair selection in Photoshop can be tricky business. Trying to select the hair by manually erasing can be very tedious, and often will come out looking unnatural. Fortunately Photoshop from at least version 7 and up has a great tool for hair selection. As with most selecton tools, it will perform better with a high contrast background. In fact if you have dark hair with a white background, it will select hair nearly flawlessly. Pretty cool stuff here. Just be sure after all your hard work that when you print it you use a nice printer and printer ink to show the detail you put into the picture.
This is the image that I will begin with.
From the file menu select Filter/Extract. You should end up with a window similar to this.
The edge highlight tool should be selected. What you will want to do is to go around the edges that you want to select. Only highlight as much as is necessary to select what you need. Wherever you can see through the hair to the background, you will have to make sure that those areas are also highlighted. Make sure that you select all the hair whisps as well. This will really make it look good when you apply a different background. Change the brush size as needed to accomadate your selection area. Notice how I use a brush large enough to select all of the hair areas that you can see through as well as the whisps. This little girl has a lot of whisps, so it should be a good example of how well this tool works. Also notice that when I can't see through to the background that I only use the very edge of the brush.
Next you will want to grab the bucket tool and fill inside of the highlighted area and click OK.
As you can see it has Photoshop has selected very well. If your first try does not turn out as you would like, try it again with a different brush size or highlight a little more or a little less of the edge. You will get a feel for it after awhile.
I like to check how well the selection is by adding another layer underneath and fill it with a white or yellow. The high contrast allows you to see any flaws there may be. Once you have it how you like it, drop any background you want underneath it.