The X= blog has a good post on using Lightroom’s develop tools to sharpen your shots.
Whilst previous incarnations of the sharpening tools in Lightroom might have disappointed, the tools available in v2 are much better. Unless you are specifically after a blurry finish I would advise you to always sharpen your images taken with a digital camera – but make sure its one of the last things in your workflow you do.
The x= article covers the amount, radius, detail and masking sliders, talking you through and showing you what each does. Personally, I’ve found the masking slider incredibly useful especially when your image may contain areas with a little noise that you don’t want to sharpen.
You can check out part one of the article at the link below. This covers the develop module sharpening tools. A planned second part will cover using the export sharpening options.