is it a facebook only app? is the idea so simple and obvious that you're scared to even say what it is? are you just the idea man or are you also going to be doing some development work on this project (css + javascript count)?
I currently have two other developers on my tean.They are assigned different individual apps to work on. I polish the apps once they are made and take care of the business aspects. I also handle all of the software and data base design. We are working on some pretty interested facebook apps. I'm very excited about the work that we are doing. Face book right now is like the California gold rush. A lot of money and hype around it. i'm still looking for 2 more developers for flash,php/mysql.
I'm in the same boat, i need one or two more devs... i think in terms of complexity to implement your app(s) and mine are more or less on par...