I think that a Mod should move this over to the Bewares Forum.
FWIW, I don't think it's a scam, but it is a bad idea - not least because the organiser seems to be completely clueless.
For example, the competition is judged on the basis of a book proposal, which includes 1,500 words of actual book text. That would be fine if it was an initial sorting device to establish a long list, but it doesn't seem to work that way. Closing date for entries is 13th July 2011 with the top 50 notified by 24th July 2011 (i.e. they're allowing 11 days after close to complete their evaluation) and then a dinner on 31st July 2011 where the 2 winners are announced.
That timescale is completely unrealistic and I don't see how you can possibly have a winner awarded a book contract if you don't have an actual book to judge.
In any event, in return for your $50 or $100, the fact that the Grand Prize is stated to be a publishing contract up to $15,000 suggests to me that it's basically a book packaging deal of the kind that any pay-to-play operation (which Wheatmark basically is) where sure, you'll have a book at the end of the day - but without bookstore distribution, marketing, promotion etc you're little better off than if you'd just done it yourself on Lulu.
All in all it smells like an amateur operation to me and your book undoubtedly deserves better.
MM