I just recently downloaded Google Gears so I could edit my text documents offline (no internet access). I clicked on the link Offline and I got started downloading Google Gears, allowing it to always trust the site http://docs.google.com. I unplugged my internet and clicked on the Google Docs Offline Icon I created when I downloaded Google Gears.
It worked like a charm. I edited the document (I could not create a new document) I could format it, and rename it. Then I plugged in the internet connection. I went to docs.google.com and it synced up. When you edit something offline, it has a light yellow tag next to it letting you know it was edited offline, once it’s synch up again, that tag goes away. Right now, the offline feature only works for documents (not spreadsheets and presentations). You also want to do offline editing on a personal computer and always on the same computer so your changes are always properly synced and reflected correctly in your online version.
I had it freeze up on me a couple of times, but this is a nice feature to add to the Google Docs and Spreadsheets app. Check it out if you have the Offline link available next to your Google account name in the top right hand corner. Enjoy!