Welcome to the board Kelly
I'm always willing to help people out in need of hair! :B
Here you go:
1. Open an image that needs hair and make foreground/background colors black/white
2. Open a image X of someone else, in this case a woman
3. Select the move tool (5)
4. Click with the mouse cursor on image X, hold mouse button and drag it on the other image (this will create a new layer)
5. change the opacity of this new layer to about 50% (4)
6. go to the top menu bar and select 'Show bounding box' (7)
7. resize image X on this new layer, by dragging the corners (hold the shift button to constrain proportions!), until eyes and mouth match with the image underneath, click in the middle of image to move image around
8. when done, change opacity back to 100% (4)
9. Add a layer mask (click on icon (1)) to this image
10. Select the brush tool (2)
11. Click on the layer mask to make it active (you'll see a double border)
12. Paint with
black on the mask to make areas
invisible (transparent)
13. Paint with
white on the mask to make areas
visible, in this example the hair
Click on icon (3) to quickly switch between white/black (switches background/foreground colors).
Change softness and size of brush depending on the situation.
Always make sure when you paint, that the layer mask is active! (double border). Just undo your brush strokes if you paint on the image by mistake.
When done, make the layer with the new hair active and adjust lightness and saturation. Make sure the image is active when you do that and not the mask (mask will have single border).
Just one way to do it
Have fun!
Hello there - new user in need of hair!! 
Linear Mode
