Facebook integration so users can register with facebook login details.

Hi there i need a little help. I have a website designed and coded ready. However I am stuck on a small part.

I have a place where users can register, now what i want is the user to put the registration details, for example name, tel, email and then they have to put their facebook login details(username and password) which will then automatically complete the registration.

Once the registrations is completed i want all the details to be sent as an email to my self.

also i would like, a small button under the registration which lets the user "share" the detail of the website with their facebook friends, so when they tick that box a line saying for example "join peopleperhour - and hire freelancers" with a link to my site.

now it should also have an option so if users dont want to sign up using their facebook details they can just click a button and the requirement to put in their facebook details will not show.

I hope this makes sense, so the design and coding of the site will be done, i just need someone to be able to code this little bit into the design.

thanks and see attached image as an example