Voice Emulator?

Hiya guys!
Okay, so I'm working on a song (I do music from time to time, nothing extreme,) and I need to find a hopefully free text-to-speech Voice Emulation program. I'm hoping to find one with multiple voices, including the classic Stephen Hawking voice (you know you know it!) and maybe a "flat" monotone voice. Any links or suggestions?

do a search for 'text to speech' some of the realistic voices cost about 45 dollars each. The steven hawking one comes free with windows.

It came free with an Amiga 500. You'd think he'd get a new one.

FL Studio has one, on the off chance you're using that.

You may have some fun with THIS ONE

This is great fun, and it has a couple voices. I can't say the name on the forums but here's a link:

http://unaesthetic.net/st/dl.shtml.

He has. Apparently he's now using Neospeech.

Look for something called Vocaloid by Yamaha