Accessibility option in Android 2.1
You need to install apps that are classified as "Accessibility Apps". The most used ones are part of the Eyes-Free suite (Talkback, Kickback, Soundback, Accessibility Preferences, Eyes-Free Shell, Talking Dialer, Rock Lock, Walky Talky, Intersection Explorer), plus several useful 3rd party apps such as IDEAL Web Reader, IDEAL Magnifier, and K9 Mail.

More info - https://eyes-free.googlecode.com/svn/trunk/documentation/android_access/enabling.html