http://ebookplus.com/
Pays $0.07 per chapter that gets read. Says it's aimed at people who pirate ebooks, but I can't really see those type of people being interested unless it is really easy to strip out the adverts (which presumably would mean you didn't get paid).
I think it's more likely to attract people who already pay for their ebooks, either as an alternative to paying for anything, or to increase the number of books they can read on a limited income.