Here is a list of the other sites that we found useful when compiling our checklist.
Make Word Documents Accessible (WebAim)
Make Word Documents Accessible (Microsoft)
Make PowerPoint Accessible (Microsoft)
Make Excel Documents Accessible (Mircrosoft)
Arts Council England Action for Access 2004
Adding captions to Facebook and YouTube
Government posters about accessibility
Tagging PDFs in Acrobat (WebAim)
Converting from Word to a tagged PDF (WebAim)