Following the launch of Google Docs viewer with supports of .doc and .docx attachments. Google now released a "mobile version of the Google Docs viewer for Android, iPhone and iPad to help you view PDFs, .ppt, .doc and .docx files you've uploaded to your documents list, without needing to download the file.
With our mobile viewer you can switch quickly between pages and pan/zoom within a page. On your iPhone and iPad, you can pinch to zoom in or out," said Google.
You can try it out by going to docs.google.com on your Android-powered device, iPad or iPhone and select any document in these formats that you've previously uploaded.