I think recording family history is important. I have stories and interviews with several family members. The files are just sort of hanging around my house right now. Eventually, I'll put it all together as a gift for my relatives and kids.
Start with Your Life as Story. It's more geared toward personal memoir, but the advice will work just as well for a family-centered work.
Interview your family members. Set up a camera (off to the side so it's not distracting them) and just get them talking. People will claim they don't remember much, but once you get them going more and more memories will pop up.
Your aunt doesn't have to be a good writer to write down the stories. Just ask her to write down the facts of what happened and you can re-write it later on. The important thing is to just get the information down first. You can go through what she wrote and pick out the most interesting bits and follow up with relatives to find out more about those particular events.