Google Docs Viewer allows users to view any document files online via the browser. In order to view documents online, just enter the URL for that document file and Google Docs Viewer will display the document online via your browser without the needs for any plugin.

All viewer URLs should use the path http://docs.google.com/viewer .

For example, if you wanted to view the PDF at the URL http://labs.google.com/papers/bigtable-osdi06.pdf , you would use the URL http://docs.google.com/viewer?url=http%3A%2F%2Flabs.google.com%2Fpapers%2Fbigtable-osdi06.pdf

As per Google Docs Blog:

Last year, we added PDF upload and view to Google Docs, and the "View" link for PDF attachments in Gmail. We also added support for viewing PowerPoint and TIFF files in Gmail this April. Feedback on these features has been very positive – viewing files right in your browser is fast, and it keeps your downloads folder clean. Plus, it spares you the hassle of saving your files to the machine you’re using, which could be a shared or public computer.

Starting today, we’re opening up this technology to all webmasters and blog owners with the Google Docs viewer. All you have to do is give the URL of a PDF, Powerpoint or TIFF document to us and we’ll display it directly in your browser with no download required – like this. For complete documentation, and a form to generate code for embedded viewers (example below), check out our webpage.

You need to add only few lines of code to have the document viewer on your website.

<iframe src="http://docs.google.com/gview?url=http://www.kuanhoong.com/images/sample-kuanhoong-dot-com.ppt&embedded=true" style="width:400px; height:500px;" frameborder="0"></iframe>


Simply replace the text in bold using the URL of the file you want to embed. Google Docs viewer will work only with PDF and PPT files.