Laracasts should be your best friend. This is one of the websites that changed my way of thinking and the way of programming. I believe that this is the best website for PHP and Laravel (if you plan on using it after you are done with plain PHP, few projects)
The Laracasts Forum should be your home for all PHP questions while learning.
There are a few other websites that teach PHP and/or other PHP frameworks (save them for later, don't start with a framework!!!!)
The ones I checked out were:
- Code Course
- KNP University
Whatever you choose, make sure to spend a few good months or a year with PHP and Object Oriented Programming PHP only without using any framework to understand the language and what's happening. Make sure to ask questions, people will help you. Oh, and most importantly, think of a few cool projects that might be useful to you, just so you have something to build and practice your newly learned skills.
Remember to revisit things that you already know so you can understand things better every time you learn the same thing. You will find out why it is used and how it is used in real life. That's how I learned Object Oriented Programming.
You should focus in PHP 7.0, PHP 5.5 stopped receiving support the last week, and PHP 5.6 will stop getting active support at the end of this year, so it's not worth the trouble to learn them.
Although I hadn't seen or heard about a good resource "from zero to PHP 7.0", the most I can recommend you is the Modern PHP book, but it assumes the reader has some familiarity with pre-5.4 PHP (ie. non-modern PHP).
Although it is still a suggested read when you become acquainted with the language, since it introduces you to the Composer ecosystem, the PHP-FIG Standards, the PHP Right Way, and some other gems of information.
EDIT: I did a quick search, these books seem like the most sensible choice right now:
I just skimmed through the table of contents of them, the first one looks more focused in starting from zero, the second one looks more focused in creating CRUD applications, which is the most common kind of application in the PHP world, since I hadn't read them, I can't give a recommendation, but I would suggest to read both of them, the Sklar's one first.
I don't know that I can offer much more than Aldo recommended. My method of learning is to just jump in and do it. php.net will be your biggest go-to reference. StackOverflow will be your friend.
You'll probably want a good IDE that supports PHP. There's plenty of discussions about that and everyone has their favorite.
As for frameworks, I don't think I can offer much advice. Everyone is different as to what style they like. Laravel seems to the be most popular at the moment. But there's plenty others: CodeIgniter, CakePHP, Yii, Phalcon etc., and they all do a fairly decent job once you get them up and running. It's a matter of preference. You might check job listings in your area to see what technologies within the PHP ecosystem are most sought after and focus on those.