Where can I learn more about teaching Spanish to heritage speakers?

See here for the UIC online course for heritage Spanish teachers offered every Fall. There are additional courses, textbooks, and websites for teachers listed here.

Why offer a separate Spanish heritage language course?

See brochure here.

What placement exam should we use for our heritage speaker course?

Are you looking to (1) Separate HL from L2 students, (2) Determine which level of an HL program they belong; (3) Both? 

A very short, written paragraph often achieves both goals. After a while, an experienced evaluator can look at a paragraph and decide about questions (1) and (2) above rather quickly. Here is an article about the process we went through at the University of Illinois Chicago (Potowski, Parada, Morgan-Short 2012). There is more about placement in Capítulo 10 of this textbook.

What textbook should we use in our heritage speaker course?

Materials selection:
I highly recommend these steps in this order:

Textbooks & teaching materials: See here for a list.

How (and WHY) should I create a Free Voluntary Reading library?

See these excellent resources: Mike Peto, Profe Nygaard