Anyone interested in inclusive design and making the web a more accessible place should check out Todd Kloots' latest post on the YUI blog: Enhancing TabView Accessibility with WAI-ARIA Roles and States. In it Todd explains how you can use WAI-ARIA to turn the YUI Tabview control into tabs that do not only show a visual change but also notify assistive technology of the changes happening to the interface and allow for full keyboard control.
WAI-ARIA is a technology standard that tries to bridge the issue of HTML not being rich enough to create the web applications we've come to expect. HTML describes documents, not interfaces and there are no native elements for interface elements like menus, tabs or sliders. With WAI-ARIA you can define these using a set of attributes and both browsers and assistive technology like screen readers get notified about what an element is and when there is a change caused by an interaction.
You can also find more shorter articles on ARIA on the Paciello Group Blog.