Do not, do not, do not start a public Open Source project unless you already have:
- Working code that does a useful and/or interesting subset of the project's goal
- An automated build
- Sufficient instructions to get the program running
This rant was brought to you by one too many really interesting-looking projects that thought it was a good idea to have a design phase that was open to public comment, and as a result never produced anything.
Getting people to contribute to Open Source is hard. If you do not have sufficient motivation1 to take the first, important steps yourself, nobody else is going to. At most, you'll attract a bunch of other people who, like you, want to talk about the project instead of coding it.
A bit harsh, perhaps, but true.
1 Edit: This originally read ‘skill’, but was changed after publication to better reflect what I meant to say in the first place.