Updated! Please find the new download here.
In the absence of a Dropbox blackberry application, I have created a BlackBerry web launcher for the Dropbox mobile website (http://m.getdropbox.com). The download for several OS versions can be found here:
OS Version 4.2.0 and up - Download
OS Version 4.1.0 - Download
OS Version 4.0.0 - Download
To install from your PC using the Desktop Manager please use this download.