Hello,
I don't know if this what you are looking for, but you have VoiceOver that comes with Leopard.
It makes your computer read whatever you type in a text editor, it can read html pages or describe where your cursor is, ...
Nota : VoiceOver can only read English language. (the result can be funny with other languages)
To activate VoiceOver, go to System Preferences/Universal Access, configure VoiceOver utility as you want and activate it.