Perhaps this may help?
Getting Finances Done » 3 keys to making your personal finances work as a couple
The whole site is fantastic for lots of information on everything.
Remember, she has to be committed to a budget as well as yourself, and she might have an easier time doing that if she has a specific goal to work towards. I'm not sure where you are in life, but perhaps you both want to buy a house, or retire early or something else. Purpose is key, as Steve says. And remember to find out what she wants as well as you. Why do you and her want to budget?
Try to have an open conversation about this whole topic. Find out what you both want in life. Communication as a couple is key to a successful financial life, so I would also recommend picking up some books on communication if you haven't already. Difficult Conversations: How to discuss what matters most is a great one, another one is Messages: The Communication Skills Book.
Another thing is, remember to budget personal money for both people. Budgetting is about enjoying life just a little bit more and getting in control, not being miserly or miserable.
As you might have guessed, I don't think its the system, rather the committment of the people. The best system can be in place but if the people aren't into it, it will all be for naught.
Budget-wise, you might try this kind of a budget to start off with:
Getting Finances Done » How to create a zero-based budget
Really do read the Best Of articles highlighted on the left.
I've also got a whole bunch of other blogs about couples personal finance, if you're looking for reinforcement or a bit more info. I'm sure there are plenty of books about finances and families, too. Visit your local libary.