(Almost) Everything You Wanted to Know about Sharpening in Photoshop...

Tutorial on sharpening in Photoshop by Bruce Fraser...

A Smart Sharpening Tutorial by John Brownlow...

An intelligent sharpening approach. Includes an automated Photoshop action to download....

High Pass Sharpening...

A sharpening tutorial for Photoshop...

Sharpening in LAB mode in Photoshop...

A Photoshop sharpening tutorial...