Screen zoom in Lion
In Leopard and Snow Leopard you can zoom the screen by holding the Control button on your keyboard adn scrolling up on your mouse or trackpad. But this is not the case in Lion. In 10.7 you have a small window that zooms in and out only the selected area of your screen.
Fear not, the function is still there but for some reason Apple decided to switch it off by default.
To enable it, head to System Preferences, click on Universal Access, select Seeing and un-tick the “Zoom in window” option.
The screen zoom is back on again.