A very useful livebinder by some teachers on QR codes in the elementary school with information and guides. I've found this is pretty updated even though the first page has a description from 2010. Very useful if you want to use them in your classroom or library at the elementary level.
One of my favorite youtube channels for teachers and educators is from Jarrod Robinson "Mr. Robbo the PE Geek" from down under. He is helpful, loves kids, and has a unique understanding of engaging bodily kinesthetic learners in all subjects and a passion for mobile learning.