I think that some of them may get added on to the ENA site fairly late. For NY, for example, I notice that there are six provider courses and one instructor course listed for June alone, while there are only five classes listed total between July and December.
It's funny, in our area it always seems that they hold ENPC courses on the same weekends as TNCC- except in different areas, I wish ENA could tell a course director-- "Hey, there's a TNCC already scheduled for that weekend in the same region-- how about waiting for 2-3 weeks?"
They'd get more people signed up that way, it's disappointing that they hold so few and then all at the same time so you can only take 1/yr.
go to this web site to get what you need for tncc, enpc, and catn. http://www.ena.org/chapters/default.asp. click your state and go from there. also, if you have to travel to keep your certifications up, i think your costs are tax deductible.