I think you'll be much more likely to attract interested people if you put up a project page of some sort, and the code you have so far (ideally a public SCM repository), and point people there. As roboticus already said, there are lots of projects like this. This is not a problem if your project is sufficiently different from the others and interesting in some way. But unless there is at least some minimal description of the project up somewhere I personally wouldn't even bother sending an email anywhere. The key in Open Source is "open" :-).