Hey I'm still here,
I've now got Facebook playing nice with my apps, I can get and save user data. And various other bits of information.
Still haven't looked at Payments and Achievements but I will when I need to.
I've started to look at the Parse SDK (www.parse.com) now, so I can save data to a database and bring it back within the app.
So far I've got it logging in and adding things to the database, I've got multiple users adding records into the table and the records being updated as you are playing the game. This is usefull if you want to store level specific scores and data.