My husband and I have successfully gone from a dual income to a single income home. I cannot believe how much extra money we were spending on things that were not necessary. The only "luxuries" we gave up was cable TV and cell phones, and honestly, we could probably afford to keep one of them and choose not to. We do still have high speed internet, so don't think we gave up everything ;-)
How did we start? Go to the library and look at books by the author "Rich Dad, Poor Dad." (I know, not an encouraging title for moms, but chocked full of goodies). Also, I liked "Cheapskate's Guide to Living Cheaper and Better." Another good book is "Shattering the Two Income Myth," which I loved so much I bought a used copy off of Amazon for less than $10 (and most of that was shipping). This book is nice because it starts with how to get ready, obstacles, and first steps BUT then it has one tip a day. So, you can literally read one (or at the most two) pages a day. Some of the tips are dated and some of the tips didn't work for us, but enough tips worked into our lifestyle that we were able to make a significant difference.
I am currently expecting our second child (due any day now), and even though that has caused us to relax some of our spend thrift ways -- there is no way I am hanging loads of laundry out to dry at 9 months pregnant -- we are still living within a budget. It is hard at first, but it is so rewarding to know that you are living better for yourself and setting a good example for your children.
Good Luck!