Silverlight 1.0 didn't have much in the way of accessibility - essentially the equivalent of alt tags. Silverlight 2 will change that by exposing a full accessibility tree to accessibility tools in builds post Beta 1.
In this video Mark Rideout from the Silverlight team discusses how Silverlight 2 handles accessibility. Mark was PM for accessibility in Windows Forms, and is also PM for accessibility, textbox and input in Silverlight 2.
If you have never witnessed someone using a screen reader to navigate a web page, be sure to check out this video (especially the last couple minutes where he speeds up the rate to what he normally uses)
What will Silverlight 2 provide for accessibility?
- Tabbing and tab order
- Focus and Keyboard Input
- Exposed Accessibility Tree (through UIA - UI Automation) for screen readers and other accessibility tools
- Accessibility Information directly in XAML Markup via AutomationProperties attached properties such as name and help text
- Support for AutomationPeer as in WPF
- Other capabilities such as notifications for high-contrast requirements
If you want to see the accessibility tree for your applications, download UI Spy.
In the video, Mark recommends that to get used to accessibility today, look to how it is done in WPF (AutomationProperties, AutomationPeer) and you will be prepared for accessibility in post Beta 1 bits.