Although there's no specific Dropbox plugin, you can download the Pixelpipe plugin from the Ovi store and add Dropbox as one of your pipes. If you share a file with the Pixelpipe plugin, it will then be placed in a "Pixelpipe" folder in your Dropbox.

Check out this thread for more info:

http://talk.maemo.org/showthread.php...xelpipe&page=2