The installation process seems to be not very consistent to me but this is my experience with yesterday's update to the N800 "camera" application. I browsed to the garage.maemo.org download page for the update and clicked on the new file (which had a .deb extension). I thought it would initiate the update process in Application Manager like has happened for some other updates. Instead, the "Open" option in "file download" was greyed-out and I could only "Save" the file (which I did, to my N800). Then I used File Manager to browse to the folder where the file was saved and clicked on the file that I downloaded. At this point, the Application Manager kicked in and I could proceed to "update" the Camera application. I am confused as to why it is sometimes easy as one or two clicks and other times takes more steps?

By the way, the "Search" feature at the top of the forum page (not Search this thread" works wonders in finding the answers to all your questions - believe me they have all been asked before!! Have fun with your 770.