Cutting a portrait down to the right size in photoshop.

[imported_Ziggy]

mmk, this is in photoshop. I have an portrait that is 6 in high by 6.319 in wide. I want it to be 6 in high by 4 in wide. I figure I need to cut 167 pixels off horizontaly to get it to the right size. Please tell me how to do this in photoshop.

Thanks!