I have recently dipped into accessing the Windows API in Python (via win32all), and I have decided to grace you all with this wonderful bit of joy, which I have dubbed SayIt (very descriptive). Basically, it uses Microsoft's Speech Engine to say what you type.
Python is not required to run this (py2exe is real joy), but Windows XP is.
http://www.captainkoala.com/content/Setup.exe