Where to start

Throughout this project I'm also going to explore some Agile concepts, hence I have a product backlog and will soon have acceptance criteria. To start I'm going to take a leaf out of the XP book and write a test, but first I need to elaborate my story. Story 1 was:

"As a new user to the site I want to be able to create a profile so that I can return to the site and see my information from previous visits"

so here's the acceptance criteria written in given, when, then form

1. Given the registered username of madmo2991@hotmail.com has not already been registered When a user tries to register with it, they should receive a confirmation email
2. Given the username of madmo2991@hotmail.com has already been registered the user attempting to register that user should be notified that account already exists.
3. hmm, i'll think of more later...