Tych Panel is an extension to Adobe Photoshop that automates diptychs and triptychs creation. It supports an arbitrary number of layouts using the compositing feature making it the perfect tool for your photo blog. Free

"The Pen Tool makes appearances across almost the entire Adobe product range. Its function and behavior varies depending on the application, but by mastering it youll find you work quicker, smoother and with better results. This guide will give you a comprehensive basis for working with the Pen Tool in Photoshop."

basic introduction to bezier curves and the use of the Pen tool inside applications like photoshop and illustrator

The Art of DeTouch explores the manipulation of images related to the human form. Drawing photographs from existing online portfolio sites of professional re-touch artists, this application allows a user to explore precisely how the images were altered. U

Quicktime tutorials on photoshop

Excellent explanation of Unsharp Masking

Provides a number of sharpening techniques as an "Automation" plugin. Not FREE