Photoshop tutorials and tips

This website that I came across on stumbleupon.com
has a lot of tutorials and tips as to how to use photoshop.
Some of the tutorials are:

Content-Aware Scaling


HDR Tone Mapping


Skin Texture


Smart Noise Reduction


Portrait Retouch


Grunge Effect


Color Replacement


Remove Color Cast


Grainy Effect


Wire Remove Plugin


etc.