If you ever read palm .pdb ebooks I can reccommend the desktop versions of eReader Pro - they have this awesome little 'RSVP' feature, which sticks up one word or one group of words at a time at a user defined rate. Awful name, really, but still a neat way to get through a book quickly and keep yourself form skipping backwards across a line when you're reading.
Spreeder does a similar thing (and for free), but eReader's got a more intelligent algorithim - it'll give you more time on longer words, and it can pause for punctuation. I used it last night to read a load of Getting Things Done. Great little app.