Most web browsers are able to enlarge font sizes and assist with improving the experience for people with accessibility problems below is a list and instructions for the main web browsers and how to enlarge text.
Internet Explorer
Go to view, Text Size and the chose the text size you wish to view. You can also change the colour of the page and text, and remove most graphics to make it easier to read if required. Go to 'Tools', Internet Options, Accessibility and then check the required boxes to remove colours and styles. You can then go to colours and change your colour to you required need.
For newer versions of Internet Explorer:
Click on the Page button in the right hand side of the screen and then chose text size or zoom options.
Firefox:
Go to view, Text Size and the chose the text size you wish to view. You can also remove the page style by clicking on 'View' page style, no style. You can then change the text and page colour by clicking on 'Tools', Options, Content, and the choosing the colours button.