To navigate to the Accessibility settings, click on Settings from your homepage, then select General. From that list, click on Accessibility. From there, you'll see a list of available accessibility options. This document briefly outlines the different options.

Vision-Impaired:

VoiceOver: VoiceOver speaks items on the screen. Speaking rate can be adjusted, and there are settings for speak hints, pitch changes, sound effects, compact voice, use with Braille, among many other things

Zoom: the zoom function allows the entire screen to be magnified

Invert Colors: this function inverts the colors on the screen

Speak Selection: this will allow a Speak button to appear when text is selected

Speak Auto-text: automatically speak auto-corrections and auto-capitalizations

Larger Type: allows the text to be larger

Bold Text: bolds text

Increase Contrast: improves contrast on some backgrounds to increase legibility

Reduce Motion: reduces the motion of the user interface, including the parallax effect of icons and alerts

On/Off Labels: this will display a "o" for off or "|" for on for all slider options

Hearing-Impaired:

Subtitles & Captioning: this allows closed captioning or subtitles

LED Flash for Alerts: alerts will cause the phone to flash led lights to notify user

Mono Audio: adjusts the sounds to mono; under this, there is a slider for L - R where a user can adjust the audio balance for the speakers

Learning:

Guided Access: this keeps the iPhone in a single app, and allows you to control which features are available

Physical & Motor-Impaired:

Switch Control: allows you to use your iPhone by sequentially highlighting items on the screen that can be activated though an adaptive accessory

AssistiveTouch: allows you to use your iPhone if you have difficulty touching the screen or if you require an adaptive accessory

Home-click Speed: this will adjust the speed required when double or triple-clicking the Home button

Incoming Calls: this allows the user to set the incoming calls to "Default", "Headset", or "Speaker"

Accessibility Shortcut:

Allows user to specify what triple-clicking the Home button does; options include "VoiceOver", "Invert Colors", "Zoom", "Switch Control", or "AssistiveTouch"

For more information about each of these options and their functions, please see: http://www.apple.com/accessibility/ios/