Most of the apps I've seen which offer configurable voices generally sound stilted and robotic. I've been monitoring AT&T's Natural Speech technology for a while, and it's pretty good, but I rather like Acapela's Heather and other voices now. Their technology seems to be developing quite nicely. http://demo.acapela-group.com/ Loquendo is doing some interesting things with regard to inflection and expression, also. http://actor.loquendo.com/actordemo/default.asp?voice=Simon