Whenever I'm trying out a new language, I usually check if lynda.com has a tutorial on it. I happen to know that lynda.com does have one on PHP, and if you learn well with video tutorials, you can get to a pretty good spot with those tutorials in record time. If I remember right (It was a long time ago last time I looked at them), they don't get into OOP much, but if you're coming from C++ and Java, the php docs should probably be enough to help out.
Once you've got the basics down, the best way to learn would be to come up with a simple project and hack away at it. Build a tiny CMS or a blog, php is flexible, so you can come up with your own style pretty quickly, and then learn from your mistakes.