PTO Today does offer some really good resources to make this easier. So definitely consider their membership/guides. Meanwhile, here is the basic information:

Applying for the federal exemption requires a rather complex application and a $750 fee. (But it's doable, many of us have completed it.) This make you a true charitable organization, donations to you are tax deductible, and you don't have to pay federal income tax on money you raise.

So the general order of things is:

1. Organize your group and develop bylaws and processes acceptable to the IRS.
2. Set up as a non-profit corporation in in your state. (In most states this is a simple, inexpensive process. It's optional, but desirable.)
3. File your application to become a 501(c)(3) with the IRS.
4. Once 501(c)(3) status received, file application with your state to become a tax exempt organization (mostly sales tax).

This cycle will generally take a few months. There is lots of information posted on these forums. So explore and ask questions.

Note - many PTOs don't follow these steps and never formalize. As far as the IRS goes, if your organization brings in more than $5000 per year (gross, not net) you are supposed to file for 501(c)(3) status. Otherwise, your group is simply a business and should be filing a commercial tax return each April. Many do nothing, file nothing, and simply operate in limbo. Odds are, you won't get caught. But that fact is those "limbo" groups are operating illegally.

PTO Today offers a great Start Up Guide that takes you through these steps.

I need help! I am the new President of our Parent Group
and we have just completed our bylaws and was wondering
how do I go about becoming tax exempt? it should have been
done last year but they kept stalling, the bank told us that
there is too much money in our account that we should
consider filing for tax exempt. all ideas and thought are great.