How to make a platform game
Building a platform game, a beginner's guide
Extract from the "Scrolling/Camera" section of the How do I FAQ:
crolling / Camera
TiledBackground horizontal scrolling - LINK
TiledBackground vertical scrolling - LINK
Slow vertical scrolling - LINK
Sprite horizontal scrolling - LINK
Click and drag the camera - LINK
Metal Slug/Mario type of scrolling - LINK
Zoom in/out - LINK
Camera smooth zoom in/out - LINK
Delayed/controlable camera - LINK
Example of scroll, scale and parallax - LINK
Moving the camera with keyboard - LINK
More parallax example - LINK
Flip camera/world - LINK
Example of pan with mouse - LINK
Another example of vertical scrolling with tiled backgrounds - LINK
Another continuous scrolling made out of sprites - LINK
A scrolling where the character isn't in the center of screen - LINK
Smooth zooming - LINK
Some of those ressources should answer your questions.