I recently found a handy little FREE Java-based program that works on nearly any platform. While it comes pre-packaged with a few handfuls of lame suggestions, it is rather full featured for a freebie. You can load it up with a slew of your own suggestions, control flash rate, text font/color and alpha transparency level. And did I mention, it is free?
The Cut and Paste doesn't work well with this little gem, so if you are going to do a long script, it's best to use Notepad or similar text editor to write your script then paste the whole thing into the suggestions panel.
[url=http://richard.warburton.it/fst]Click HERE for Free Subliminal Text by Richard Warburton[/url]
Cheers!