Why would I need this? Can't I just read a book?
See the About page.
What does it cost?
See the pricing/registration page.
I want to use this with my spouse. How do I do that?
I'll be adding a feature for having multiple members in a family. But for now, just like with mint.com, you'll need to just tell your spouse the email/password you're using.
What tasks/goals/projects are there for me to do?
A simple list of the Goals is here. Once you're a member, this list will be prioritized, and each Goal will have a checklist for you to follow (and customize if you like), and have Resources and discussion Forums associated.
How many Goals can I do at once? Where should I start? Do I have to do them all?

You can do as many as you like. But, in general, I recommend you stick to 1 at a time and get it done!

In general, the Goals further up the (members-only version of the) list are more important to most parents than those further down. But you can do them in whatever order makes sense to you. You can also add your own Goals.

And you don't have to ever do all the Goals, it's up to you.