Not pleased with the stock settings that allow you to change your screens brightness? XDA member fantastxmw has developed an app that uses root permissions to modify your screen's brightness. The app allows you to change the brightness from 2-255 and allow you to lock it so no other applications can edit it.

If you make a mistake, there is also a restore option. If you're interested in, it you can download it from the market or from the discussion thread in the attachment on the bottom of the original post.