If you raise your ISO too high, you can get noise in your image. Is there anything you can do to clean that up? Yes there is...
Ajja & Burn In Noise - Image Of Yourself
Advanced Sharpening and Noise Reduction in Photoshop
Reduce Image Noise with Photoshop CS5 - Camera RAW
Burn in Noise Vs Ajja - Image of Yourself
Noise Reduction & Removal Tutorial: Neat Video Tool
Read more about The Geek Mind.