I recently found an article describing the Deskbot which is one of the cooler text to speech reader programs available IMHO. Oh, and it's free! (BTW, does your TTS engine correctly readout the string "IMHO" as "in my humble opinion"? -- it should). (BTW, Neospeech's Paul reads it right, but XP Sam does not).
So what's Deskbot do? After it's installed, a small animated character appears on the screen (you can put the character anywhere you want), and then allows you to speak text in any window when it's pasted to the clipboard or when the the character is double clicked when there's highlighted text. It will also announce the time on specified intervals. And the best part is that you don't need to have loaded some special screen reader program.
You can also change options like altering the voice (pitch, speed, volume). Oh, and you can even change the character by downloading an MS Agent compatible character through the MS Agent Ring site.