You've received good advice so far.
My only recommendations are to look at what are necessary expenses vs. unnecessary ones.
For us, necessary are mortgage, car payment, day care, groceries, utilities, toiletries, clothing for kids, gas, contributions to 401K and 529 accounts.
Unnecessary (I don't mean completely, but more luxury) are cable, going out to eat, activities for the kids.
If you can prioritize what is absolutely essential, it may be easier to budget.
This housing market stinks, and our house is worth less than we bought it for 6 years ago despite having refinanced last year as well. So, I hope things turn around there.
In our case, our incomes are much higher than the cost of day care, so it is a necessary expense for us at this time.
We try to save money by doing a lot of our shopping at Costco/Sam's Club and storing the extras in closets/freezer.
We try to purchase the kids clothes only during sales, only at stores that have high quality/lower cost (Kohl's, Target, Old Navy). Both kids have wide feet, so we have to spend more on shoes, but we try to get things like Crocs when we can on sale so they always have a pair to fit into.
I cut my kids hair (and my own until recently) to save those costs. My husband won't let me cut his despite doing a good job.
We tend not to go to movies, but like using Red Box and free On-Demand movies when possible. I brown bag at work as much as possible.
We've set $15 limits on gifts for birthday parties.
We're going to ask people not to bring them to our son's 4th birthday party in a few weeks - because we know what it's like to be on that side of the economy.
My family no longer exchanges gifts at Christmas (unless nominal in cost such as photos of the kids who they don't get to see often because of distance).
Believe it or not, getting a new car recently saved us $200/month on our payment. We are putting the savings into paying down our mortgage/car early and more into 529's.
Also, doing things like a Flexible Health Savings account - reimburses for copays, Rx costs, etc. can be a big savings because it's taken out pretax.
Another recommendation is to put AS MUCH AS POSSIBLE onto a credit card such as Discover that pays cash back. We put our cell phones, cable, groceries, day care, etc. onto our Discover, pay if off in full each month, and usually get a few hundred in cash back at the end of the year.
Good luck. Sorry for the long message - hope it helps.