Project PLN was developed by a couple of educators that I follow on Twitter. Nick Provenzano and Kelly Tenkely have done an excellent job creating these great "books" for educators. So far, with the help of the members of their PLN they have published 4 books. They are:
1.) All About PLN's
2.) Best Practices for Start of School
3.) The Administrators Issue
4.) The Web Tools Issue
You can find all four issues here. I highly recommend that you read some of the entries by some great educators.