How to create an application for my Facebook Page?

I have a Facebook Page for my organization and would like a tab that allows people to sign up to our mailing list by filling out a form. I’m guessing I’ll need a developer to help me create a Facebook application… is that right? I know someone who is interested in software development who volunteers with us. How can I help him get this started? I’m looking at developers.facebook.com and a bit confused.