Internet Explorer

A simple way to adjust text size, when using IE, is to click on View, from the browser tool bar, and then Text Size. By moving the mouse to the right, a new menu will drop down, giving you the option of changing the text size.

Windows and most Linux Managers

 
For users with a scroll wheel in the centre of their mouse, the easiest way to increase the text size, is to hold Ctrl and roll the wheel towards you, as if scrolling down the page. Holding ctrl and scrolling the other way will make text smaller again.

Otherwise the following keys can be used:

Full Screen: F11
Zoom Text Smaller: Ctrl+-
Zoom Text larger: Ctrl+=
No Zoom (100%): Ctrl+0
View Page Information: Ctrl+I
View Page Source: Ctrl+U

Macintosh

Zoom Text Smaller: - Cmd+-
Zoom Text larger: Cmd+=
No Zoom (100%): Cmd+0
View Page Information: Cmd+I
View Page Source: Cmd+U