You should be able to download or side load and open it but if it is a locked PDF you may need the pay version of docs to go. Adobe doesn't seem to be offering their reader for the tablet yet maybe it will come at the same time flash support does..... I am still trying to figure out which document edditor to buy so I can't help there but there are multiple ones and everyone seems to have a favorite. Maybe someone else can help there.
My Xoom has the Quickoffice viewer installed out of the box. When attempting to open a PDF I get a pop up window asking which app to use. I select Quickoffice and the PDF open right up perfectly. Hope that helps.
Quick office will read PDF files and is bundled with the Xoom. I also installed Adobe Reader 10.0.1 which works fine,and fixes a screen rotation bug in 10.0.0, although I can no longer find it in the Android market for Xoom. Weird. I just installed it a day ago.
The quickoffice does work to view pdf files but it takes forever for each page to load in my 193 page pdf. So I am looking for a better solution than the quick office if anyone knows one.
Before I had a file manager, I couldn't figure out how to open one either, and I found aldiko reader which opens fine, but now that I have the file manager I prefer to use quickoffice