a) i recommend learning by doing. imo, start at the bottom and learn how to hand-code from scratch a single table CRUD app. then go through and clean it up. then build the same thing with a framework (i suggest CakePHP or CodeIgniter). then go through and clean it up. then build something more meaningful.

b) a quality text editor will work just fine. when doing php stuffs, i use jedit, and have used eclipse and netbeans in the past.

c) see a