You are, of course, free to choose backgrounds from any official D&D 4e source. This does include the background generation rules in Heroes of the Feywild (which I find pretty fun!).
I am going to provide another method for in-depth character backgrounds. The source is a very old book titled "Heroes of Legend" (HoL). I really enjoy the stories that come from the table rolls in this book. If you want a completely random character, you can go with my modified version of HoL which updates tables to work with D&D 4e and my homebrew campaign specifically.
I will be bringing Heroes of the Fewild and Heroes of Legend with me during the first session. You are free to choose which background generation you wish.
In all cases, I plan on spinning all of your character backgrounds into my campaign. So, in essence, you will be helping to develop the history of the world and some of the flavor of the land.
