http://www.sr.se/cgi-bin/p1/src/sing/default.asp?key=f553cXpO
I tried these phrases:
I don't like hair
please eat my brain
jesus will kill you
why did god drive there
Unfortunately, it's got a limited vocabulary (it's missing "zombie", "meat" and "spider"), so you'll need to dumb down your text to Top 40 level. Also, plurals may be trouble: "cat" and "dog" are good, but not "cats" or "dogs".
Have fun.