PHP: Help me jump-start my learning

Soon I will be responsible for maintenance and customization for a Zen Cart site, but I have never worked with PHP before.

Which "parts" of PHP, for lack of a better description, does Zen Cart use most (or most interestingly)? Where should I focus my efforts in order to do the best job in a short time?

I have been doing web development in a Microsoft environment for nearly 15 years, and I have done some pretty serious SQL Server work. I'm not afraid of learning PHP, but I want to be as useful as I can in a hurry.

Recommendations for books and/or training classes are welcome.

http://www.w3schools.com/ is a good resource.

You may not ever need to touch the php, so I wouldn't sweat it. I recommend playing around with Zen Cart and reading the information in the Tutorials/FAQ section (see link at top) before worrying about php.

For the most part, you may not need to become a "guru" in PHP. "Standard" Zencart is relatively easy to configure - either through the admin panel, or through a few very straight-forward edits to php files, that even a raw novice can do. (Plenty of advice posts on this forum, and a huge array of tutorials).

A considerable library of add-on modules is available, so for many functions you may require over-and-above the core stuff, there is probably a module available.

In general, it's best to use these add-ons "judiciously" - ie: only if you really need the function.

If you do find a need to make some particular tweak to the PHP in your site, the PHP Manual online has detailed resources.