I'm currently taking part in the 365 days flickr group for self portraits. I'm at day 91 with no days missed.
When I'm all done I intend to make a photo book of the year, I think it will be great to look back on in years to come.
I think once you are comfortable with the idea that not every photo is going to be a masterpiece it becomes a lot easier to do. Don't expect to spend ages composing and post processing each image and it becomes 'do-able'.
People that say they would be 'too busy' are missing the point, you only need a moment to take a photograph and you do not have to post it online the day you take it.
It's amazing how quickly you forget what you did on a day and how that one photo you snapped jogs your memory.