Think of a programmer as a being an auto mechanic. Trying to 'attract' programmers to an idea, is sort of like saying "I have this idea for a car, and I just need someone to buy it and put it together for me." A successful open-source project would be likened to the experimental 'kit' car your neighbor is always tinkering with in his garage. He probably spent 2 years working on it solo, and now its far enough along that some of his auto-mechanic friends got excited about it. They come work on it every weekend because it interests them.
Stop thinking that there are a bunch of programmers that are just out 'looking' for a project to donate time to, any more than auto mechanics spend their saturdays going door to door offering to do oil changes. Every project I have ever been involved with, and every person I've known who has worked on a project, has done so because the project was useful to them already. Open source development tends to be 'evolutionary' which is why most of the really successful projects tend to derive from an existing codebase (Think Firefox, etc...)
