This is a bit of news to me, unsure if anyone else knows about it either yet.  While browsing the web, I saw a post stating that you can view PDF strait from Gmail.  As I use Gmail constantly I thought this was a great addition.  To view the PDF, select view (its next to download), this will open up Google Docs.

I have tested it on Chrome so far, and it pretty fast, alot better then having to download the file and then open Acrobat.  I have heard that it had a few issue's on Firefox, but seems to be working now there also.