A Modern Web Development Syllabus
Chosen is a javascript plug-in that makes long, unwieldy select boxes much more user-friendly. It is currently available in both jQuery and Prototype flavors.
A minimal CSS grid.
"A simple and minimal fluid grid system that can flow inside any fluid or fixed container."
MobilyBlocks, a jQuery plugin (2KB) that allows you to create an unordered list as an animated circle.
JPolite V2: A Lightweight Portal Framework based on jQuery Think a rougher, less-polished Netvibes. V3 might really shine.
Horizontally Centered Menus/Tabs/List, no CSS hacks, cross browser.
10 Useful Flash Components for Graphing Data
A list of recommended reading for the Interaction Design program of the School of Visual Arts.
Ask Slashdot: Freelance Web Developer Best Practices?