first go to toolbar
it is in office 10
>more commands->show all commands ->speak selected text -> add this

now select Ur whole text and press speak toolbar
"now enjoy"

in older ms word
try this
Click on the View option at the top of your Word document. Open the Toolbars option.
Click on Speech. This option should be located at the bottom of the Toolbars section.
Once the Speech box has opened, click on Speak Selection icon at the top of the Speech box.

actually works once i figure the toolbar,lol

..in office 2010 look at the top left corner 4t item fro the left corner "a drop down menu" click on , then click on more commands ,,,,