There are some improvements to make over this design:
-Take apart the webcam and replace the existing lens with one of the magnifying ones. This should fix some of the image distortion.
-Build in some LED lighting to illuminate the board, removing the need for an external lamp.
-Find a combination of lenses that act like a telephoto (zoom) lens rather than a macro lens. This will allow you to have the camera higher up and reduce the chance of bumping it with the soldering iron.