Helen Bradley – Pro Photoshop and Photography: Understanding the basics of Sharpening in Photoshop
Sharpening is one of those everyday tasks that most photos can benefit from. In this post I’ll explain what sharpening is, when you should perform it and how to do it. The information here, although it is explained using Photoshop, is relevant to all photo editing programs
Helderberg Photographic Society 
Thanks for the post Steve.
Sharpening is voodoo to many people and this post is a simple introduction which will work in Photoshop and in practically all other programs too. Hopefully it helps remove some of the mystery surrounding the process.
cheers
Helen