I'd say that
w3schools[
^] is a straightforward starting point.
However, I've found that there's no easier way to learn a language than to write lots of code in that language - not just "assignment-type" code, but code that actually does useful things for you. I recommend just diving into a project and learning as you go.
As for software, you could always try Visual Studio with some PHP plugins (you can find them here and there, try
googling for one).
If free is your thing, try
Notepad++[
^].