speeches that changed the world is a good start, featuring some of nelson Mandela and many others. Simon Sebag Montefiore is the author (compiler). the two ISBN's are ISBN-10 1847240879 and ISBN-13 978-1847240873.
The best source of speeches is the Internet. Google "famous speeches" and print out the ones of interest. Books may collect some based on theme, not quality or note.
