Some time ago I wrote a short review of the file-storage service Dropbox. I listed the lack of an iPhone app as one minor drawback. This has been resolved now by the release of a free and quite handy Dropbox application on the iTunes AppStore.
The app not only allows viewing all the files on your Dropbox, you can also download files for offline use or you can upload photos from your iPhone. The application is fast and responsive and seems quite stable.