I need a list of teachers unions throughout the country that have 1500
members or more.  Need name of a contact (either the president of the
union or the information manager), address, and phone number.

There are simply too many of these unions to list here.  The American
Federation of Teachers, AFL-CIO, is the largest union in the United
States, representing over 1 million teachers.  The link below is to
the AFT State Federation websites; presumably the states that are not
represented do not have teacher's unions per se.  Each of these state
sites contain links to the local AFT unions, and from there contact
information is available.

http://www.aft.org/web/stateweb.html

Hope that this helps.