A spokesman for Dropbox, the excellent cloud-based storage and synchronisation service, has stated that while there are no current plans for a Dropbox app for Windows Phone 7, Dropbox are open to the possibility.
We receive a lot of requests for Dropbox clients for devices like those running Windows Phone 7. We do not have any plans to create a client for those devices at this time, however, we may decide to do so in the future if enough users express interest. The best place to make such a suggestion is Votebox – available at dropbox.com/votebox (you have to be logged in to access). You can check out and vote on other user suggestions and submit your own for others to vote on at that site.
In the meantime, if you want to access Dropbox on your mobile device, you can do so at m.dropbox.com.
While third party Dropbox efforts (like mine!) exist, it would be great to see an officially supported Dropbox app on WP7 devices.