Correctly Applying an Open Source License [closed]

Answer 1

Short non-lawyer answer;

1. Nothing except making it clear to anyone that you, the sole author of the code, license the code under whatever terms.
2. It is advisable to have the license file in the root directory. I would personally add in the "top comments" of all files the line Copyright 2010 . Released under in . The last part is so that you can claim that the license was never meant to be interpreted under any other law than your local (so you can get a competent lawyer in your home country in the event that everything goes wrong)
3. I would say that this depends on the license you choose

For further info, read this book - or consult a lawyer with experience of software licenses.