MOE 365 is not associated with any school or district, and gets no support from any school (a continuing source of irritation for us, but I digress). We currently have students from 17 different schools. We formed a 501(c)(3) in 2003 to help with fundraising, but now supports two FTC teams as well. (Each team does their own separate fundraising).
We gave a presentation 10 years ago on how to become a nonprofit entity. Here is a copy of the presentation; the links are dated but the basic information is still the same:
http://moe365.org/moeu.php