Re: Voluntary Product Accessibility Template (VPAT)
The Gnome accessibility project developer pages are a good place to start: http://developer.gnome.org/projects/gap/guide/gad/
If you follow good Gnome development practices and use standard GTK and Gnome widgets the application should work well with screenreaders and such out of the box. On the KDE this will not be available until KDE4, but you can make an application feed it's text information to the KDE speech system KTTS directly, as Konqueror does.
Henrik Nilsen OmmaUbuntu QA Team Lead