This is a collection of resources I use on a daily basis (or want to use in upcoming projects).  I'm always finding out about new resources for web designers, so I decided to start making a list.  It's hard to remember everything you hear in your travels...

jQuery

• Event Bubbling / Preventing Default Behavior Guide - a blog post that covers the topic of event bubbling and propogation.

CakePHP

• Available constants - helpful to know what variables are available from any part of your application

Fonts / Typography / Font-face

• Font Squirrel - this is awesome... free fonts for commercial use! Yes, use these fonts any way you want without guilt or conscience.
• sIFR - never used it, but it's ubiquitous.  I will probably start using a js only option below, but this list wouldn't be complete without it.
• Cufón - without the limitations of flash; uses native javascript. This one comes highly recommended.
• Typekit - a way to embed fonts on your site.  I haven't checked it out yet, but that's why it's in this list.

Uploading / Large Files / File Manipulation

• SwfUpload - great flash utility that gets around the max_upload_size in PHP.  Plus, it's CSS-based and you can integrate it seamlessly into your application.

Neat Tricks and Cool Things (without flash)

• jQuery Maphighlight Plugin - will highlight the "hotspots" on a traditional HTML image map.  This adds a bit of flair without the need for flash.
• AjaxLoad - will generate a transparent, web 2.0 certified ajax loader animated gif. 

Multilingual Website and Unicode Resources

• Multilingual Website Guide - discusses unicode implementations and pitfalls of different methods.  Good background/starting point.
• W3C Header/Charset Guide - the recommended header for multilingual websites (spoiler: Content-Type: text/html; charset=utf-8)
• Thesis on Curly Quotes - dense and technical. Overview of using curly quotes (smart quotes) in HTML, XML, etc.

Mobile Website Development

• .Mobi Ready - online testing of your webpage to see how .mobi ready it is
• W3C Mobile Best Practices - this is a must read; technology agnostic but some really good UI considerations and some best practices every mobile website should adopt

Search Engine Optimiztion and Marketing

• SEMJ.org - Search Engine Marketing Journal... advanced topics on SEM

Validation Services

• RSS/Atom Feed Validation