I know, but I can dream, can't I? WebMatrix is horrible compared to Aptana
I don't think PHP will be supported any time soon
OK, let me rephrase my reply:
no, it's a terrible place to learn from http://w3fools.com/
I'll agree, that after reading your link, it has a lot of smaller errors that could make a web developer end up using horrible practices when he designs websites IF he decides that he's going to only read W3Schools and no other source of information, but I still stand by my assertion that W3Schools is a good place to start. The big barrier to learning web design and programming is that many people just don't know where to start - which is why I first learned C# instead of Java or another language (though I did dabble a bit in C); Microsoft had a very nicely-written introduction to C# on MSDN which walked you through the steps. W3Schools makes it easy to understand the basics of languages, but it is true that there are many more better and more accurate sources to learn from _after_ you have the basics down.
EDIT: but reading over the OP again, it seems you've already gotten the basics out of W3Schools, so it's time to move on to MDN