KingKrool said:^^Yes, but that post processing tends to blur stuff up...
Anish said:^ Yup, basically NR is inversely proportional to sharpness.
As you sharpen an image, it gets more grainy so that converse acts as pseudo NR.
A 'proper' NR software like Noise Ninja or one of Fred Miranda's PS plugins, will analyse the image and selectively take off chrominance noise and luminance noise.