Significant changes to the Refine Edge dialog take masking hair to a new level. The choices are daunting, but the steps are simple: make a selection with the Quick Selection tool (W); Option-click (PC: Alt-click) to remove unwanted areas; then continue to Select>Refine Edge. Using Black & White (K) from the View menu, choose a 10-15 pixel Radius, enable the Smart Radius checkbox, and voil ! Use the Option-click (PC: Alt-click) method with the new Refine Radius tool (E) located in the Refine Edge dialog to refine the final mask.
Adobe Photoshop CS5
By Bryan O'Neil Hughes