How about: Write up a short synopsis/prospectus of what you want to do and take it to the Superintendent,Principal, or Music Teacher. Be sure to include ages targeted, time span and what you expect to earn and accomplish. If they (can't) pay you, most states have an Arts Council that does grants for this kind of thing. I do a lot of school programs for free, just because I want to. Once the word gets out that you are willing, the TeacherNetwork will kick in and they will call you. St. Pat's is a great time of year to do this, or most any holiday--you can tie the holiday theme at school to your program.