Check out Misterhouse. It is a very cool project for cross platform home automation in perl. There is code in there for playing mp3's and text to speech across platforms. It would definitely be worth a look.
Cool project indeed. Problem is though, that from what I read at the site, it uses all kinds of 3rd party stuff on the different platforms (Festival on Unix, M$ solution on Win32), and I'm looking for a neat solution with only 1 interface on different platforms.