With cloud-based sharing, a friendly interface and decent functionality, Box.net is one of the better file storage solutions for the iPhone.

Key in differentiating Box.net from other apps is its use of cloud-based sharing. Most of the storage apps available from the App Store, like the popular Airsharing, use a local HTTP server over Wi-Fi networks, limiting their scope and use to within that network. Box.net’s iPhone app, however, is an extension of Box.net’s established cloud storage database, allowing users to use the service through Wi-Fi or via the iPhone’s 3G connection. Consequently, the service isn’t limited to a small range and the files won’t be lost if you need to format the phone.

There are obvious similarities between Box.net’s Net-based service and Apple’s own MobileMe. This isn’t surprising, but Box.net extends the service’s reach and fills the functionality gap left by Apple.

Prior to using the application, users must sign up to Box.net’s service, a pain-free, one-step exercise that gives users instant access to a 1GB storage box. Though this space seems paltry in comparison to Gmail’s 7GB of storage and MobileMe’s 20GB, both are limited to e-mail attachments on the iPhone, and the latter also attracts a comparatively substantial fee. Box.net does offer 5GB and 15GB of storage for a fee, but for the purposes of use on the iPhone, 1GB is certainly plenty to store and remotely retrieve that much-needed document or photo.

Unfortunately, there are some limitations to the app. Uploading from the iPhone itself is limited to photos, with no ability to upload notes or audio files — these are only accessible from the phone provided they’re first uploaded from a computer. Still, the app does give you the ability to take a photo on the spot, or browse and upload from the phone’s photo library.

The user interface is extremely simple so don’t expect a comprehensive options list, though one isn’t necessarily needed. Users are able to login/logout and upload photos, as well as update the file list at will. The list itself is much more minimalist and smaller than those of other storage apps, making large amounts of files easier to organise without any compromise in useability. Once a file is opened, a “Share” button appears in the top right hand corner, facilitating easy forwarding to others via e-mail.

The simplicity involved in the execution of Box.net makes us wonder why Apple didn’t do it in the first place. Copyright and privacy concerns aside, Box.net gets rid of the need for fiddly email attachments by providing a minimalist application that gives instant access to a user’s storage box.