My wife was using her MacBook a while back and she asked me if there was a keyboard shortcut for the Home, End, Page Up, and Page Down keys. You see, Apple's USB keyboard has those keys but the condensed laptop and wireless keyboards do not. Luckily they're still there, just hiding. The secret is the function (or fn) key. The function key is a special modifier key that when held down changes what certain keys do. If you hold down the function key and press the arrows on the keyboard you will turn the arrows into the Page Up, Page Down, Home, and End keys. Let me break it down:
fn+↑ = Page Up
fn+↓ = Page Down
fn+← = Home
fn+→ = End
While we're at it there is one more function key trick. If you hold function down and press the delete key it will do a forward delete instead of a backspace.