If you are not familiar with the Google Documents List Data API (our Documents List Data API Profile), it allows client applications to upload documents to Google Documents and list them in the form of Google Data API ("GData") feeds. Until recently, the API enabled users to download files in their original format, but the developer community was active in requesting exporting capabilities, and today developers can use the API to download documents in a variety of formats including PDF, Microsoft Word, SWF, RTF, and Open Document Format.
As discussed on the Google Data APIs Blog:
Many of you have been waiting patiently for the ability to download your Google Documents using the Documents List Data API. Today, I am very happy to announce the API's top feature request is finally live.
The undocumented (but widely used) RawDocContents URL has been replaced by a more versatile Export servlet. Authenticated applications can now download documents in a number of different formats including pdf, doc, ppt, swf, xls, and more.
This is a great upgrade to the Documents List Data API and it has yielded the potential for client applications that enable users to manage and manipulate their document files in new ways. One potential new app would enable users to delegate download-only access of some of their Google Docs in the read-only PDF format. Another potential new app could use the API to batch process file format conversion in the background (write once and save in many formats).
Interested developers should review the Documentation available in the Developer's Guide and the Reference Guide as well as the Java, .NET, and Ruby on Rails samples. Once you finish your new application, be sure to promote it in the Solutions Marketplace and here on ProgrammableWeb.