If you are using one of the recent Linux distros, BT support should be there.

I am using Fedora Core 3 at home, and BT file exchange works fine.

Directory browsing is not (yet) supported, but you can install an obex server if you would like. I have not done this on my desktop, but I did install the sobex server on the 770. With this, I can just right click on any file in Nautilus and send it to the 770.

It's not geally suitable for 1/2Gig movies, but for small files it works fine. Just remember to turn it off when you are done, because having BT services working all the time will have an effect on battery life.

The sobex server is available from:
http://www.mulliner.org/nokia770/