Heavenly,
Unfortunately what Laura is telling is often the case.
That doesn't mean there aren't legitimate courses and teachers to lead you to certification.
Myself, I'm taking teacher training from an examiner for the ISTD (Imperial Society of Teachers of Dance from Britain). This is definitely not a 6-week course. It is 3 levels of certification (4 if you count the Student Teacher category) that can take years of study and experience to achieve.
I'm following ISTD but could have just as easily followed CDTA (Canadian Teachers of Dance Association) that mirrors the ISTD Syllabus.
If you're aiming at teaching International Style you'll want the grey book for Standard (and the 5 red books for latin) that can be found for sale on this site.
Most people start with the standard first. You'll want to work through the book with a competent teacher (who wants to teach rather than just make money off you).
ISTD recently opened branches in the US and there are lots of ISTD Examiners around.
I looked at Dance Visins curriculum and it seems similar.
You might also consider checking BYU out too as they have a large ballroom dance curriculum.
BTW: Laura,
Don't know if you saw my other post.
You mentioned dancing and taking lessons with a Canadian Champion now. At lunch today someone mentioned Y.R. is dancing in California now. I thought you mentioned you live in California. Possible?????
OB