With all of this talk about the jQuery library, I sometimes forget to mention the resources that make getting up to speed in this great library very easy. Two great sites have been built to help introduce developers to the jQuery library. The two sites are:
These two sites provide step-by-step guidance on how to do such things as using Ajax, incorporating drag-and-drop, creating rounded cornders, and improving the performance of searching for DOM selectors. They're really worth checking out and will certainly help you become a better jQuery developer.