Adobe today released Acrobat Reader 5.1, the latest version of its application to view, navigate, browse, and print PDF files. The update adds new capabilities for e-government initiatives, digital signature validating, and the ability to open file attachments from directly within Acrobat Reader. Version 5.1 also allows users to send emails that attach the open Adobe PDF file without switching to your email application. Acrobat Reader is available for Mac OS 8.6 or later and Mac OS X.