Here are some of the more valuable resources which you can use to further your Graphic Design or Web Development expertise:
Adobe Photoshop CS2 30-day Trial
Photoshop CS2 is an invaluable resource for any web designer and if you haven't already tried this software, I highly reccomend you download the 30-day trial.
DaFont - 7000+ Free Fonts
DaFont offers a vast range of fonts, more for free. This website is useful for any graphic designers out there into fontography.
PHP Manual - Explainations of each and every function.
Released by the PHP Developers themselves, PHP Manual can help you with any problems you may be having within the PHP language. This website may just become a Web Developer's best friend. ;)
Wikipedia - Detailed information about everything.
If you're run into a term you don't understand, SEO for example, you can go right ahead and search for it on Wikipedia and understand it to a quite detailed extent after reading the page of information offred to you.