Dropbox is already a massive help to a lot of people; syncing content between devices and allowing users to share large files and photos easily.
Now it's launched the iPhone app it means that you need never be without that essential file, or feel like your head's going to explode because you've lost track of the whereabouts of the latest version of that novel you've been working on.
The app itself is free, and you'll have to sign up for a Dropbox account to use it. But never fear – the basic 2GB account is also free, so there's no reason for not giving it a go now. If you fancy a bit more storage and some more sharing options, you can pay for an account with up to 100GB.