First off good for you, this is a really big endeavour and many have tried and not gotten very far with it. But if you are a determined person and passionate about your cause, then you should first pat yourself on your own back. People like you make all the difference in the world today. So enough with that lets get into what to do to really get it going.
1. Setup a goal of what you would like to accomplish in the first year of being up and running. This is a great first step because you want to have your goals on paper and in a checklist. It is said that 5 hours of preparation will save 20 hours of execution.
2. Figure out where you are going to obtain your funding sources. A good start would be look at what it will take to do fundraisers, silent auctions, etc. Then you might want to first get some money and support from Foundation Center. There you can find all sorts of information that is out about how to get funding and then they have an excellent directory to use to make it easier to find the places to get the funding.
3. Get a good understanding of your states regulations and what is needed to please them to develop a 501(c)(3). Of course I would suggest you either go down the route of using Nolo or going to source the government.
4. Once you have everything in place for your state you are 50% of the way there. This seems to be half of the battle, next make sure that you are all good with the IRS. You want to make sure that you are covered and going to be tax-exempt. You can make sure of this by filing out the proper forms. The form that you will need to start with is the Application for Recognition of Exemption Under Section 501(c)(3).
Be patient with this last step as it will take some time for them to get everything together. Honestly have you ever had anything that dealt with the government be a short process?
This is of course just the start of everything. But it is a very good start. Getting all of the legal and government stuff out of the way is the best first steps. As it will take the longest to get going. But once you get past this point it will become easier with the other things you do. This should give you the gusto to keep the momentum going.
Good luck with everything.