is a very crisp TTS eng-us voice that works with sapi 5 and above versions. unfortunately anna only comes with vista and is not available for download.. but she comes with ms maproute2007 program.
to install anna on all other win versions..download both files at this link:
http://deboraguarda.com/debora/ROUTE2007/Streets/MSMap/Redist/MSTTSEng_21/

save them both in same directory and run msttsengine.exe

-open your sapi(speech) settings from the control panel..and select anna from the installed voices.

preview anna there:
http://www.speakcomputers.com/windows/vista/microsoftanna.aspx