Adobe Acrobat Reader (PDF Files)

Windows and Macintosh
This download allows users to view PDF files.

Adobe Acrobat Reader Accessibility Plug-in (PDF Files)

Windows
This download allows users with Acrobat Reader to convert standard PDF files into tagged PDF files which can be read by a screen reader for greater accessibility. Unfortunately, there isn't a Macintosh version of this plug-in. More information is available on Adobe's web site.

Apple QuickTime (MOV files)

Windows or Macintosh
This download allows users to play QuickTime movies.

Macromedia Flash

Windows
This download allows users to view Flash Animations. 

MS Word (DOC Files) 

Windows
This download allows users without MS Word to open and view Word 1997 and Word 2000 documents. It also allows Word documents to be read by a screen reader for greater accessibility. 
  
MS PowerPoint (PPT Files) 

Windows 
This download allows users without MS PowerPoint to open and view PowerPoint 1997 and PowerPoint 2000 documents. It also allows PowerPoint documents to be read by a screen reader for greater accessibility. 
  
MS Excel (XLS Files) 

Windows
This download allows users to view Microsoft Excel files.  
 
Real Player 

Real Player for Windows
This download allows users to access streaming media. 
  
Windows Media Player (WMA Files)
 
Windows  
This download allows users to play Windows Media files.