The basics of PHP are easy to learn.But it's a language with many options to extend your functions.But just take some scripts and have look at them. Try to find out what they mean and what they do.Of course, you can also find many tutorials and books about PHP.It's just what you like.
I'm using Notepad, but if you use tabs the right way, its really easy to work with it.I mean:if(){ Then}else{ if(){ Then }}That 's not difficult.But I like also PHP-Designer 2005.I think it works nice, except the FTP-function.