They are in a magazine format.  I just picked up volume 3.  Not sure how oftent hey are put out, but I have to say I really like them.  Barely any adds in this issue and lots and I mean lots, of helpful articles.  This issue had at the end different projects you can try at home. 
Not sure if this is the same for other issues.  Anyone have more experience with these?

I paid ten bucks for it.  But the info in this issue was well worth it in my opinion.  Has several articles on use of a flash also.