Google released a mobile version of the Google Docs viewer
for Android, iPhone and iPad today. You can now view PDFs, .ppt, .doc and .docx files that are uploaded to your documents list, without needing to download the file.
I'm viewing more and more office documents on my Iphone and IPad these days. Since I'm exclusively using Google Docs as my office suite, this is a pretty big deal.
You can try it out by going to docs.google.com
on your iPad or iPhone or Android-powered device and select any document in these formats that you've previously uploaded