The Yahoo Design Pattern Library is a great place to get ideas for adding visual cues to Ajax transactions and effects.

Think of Backpack Journal as Twiter/Facebook Status for Projects. Another great piece of work - so simple, so well designed, so useful. See it in action.

Nitobi have just introduced a set of UI extensions for Dreamweaver. The most impressive is Spotlight which allows Dreamweaver users to create a step by step guide that loads, dims the page and uses callouts to highlight functional elements (defined by an id) on a page or application. A great way to introduce new users to an application and draw there attention to new functionality or functionality they may not be using! Check out the demo vid.