Back in April I wrote an overview on online file storage services that work with smartphones. I’ve been recommending Dropbox primarily because it provides 2 GB of free file storage, which has been the most you can get for free. Box.net is causing me to have to change that recommendation if the choice is based purely on the amount of free file storage and the existence of smartphone apps because they have increased their free storage from 1 GB to 5 GB. Box.net apps are available for iPhone, Android, and Blackberry smartphones as well as the iPad.

One reason I’ll continue to use Dropbox is that it synchronizes files to my desktop platforms. Dropbox runs in the background on my Windows and Mac computers and whenever I add a file to my Dropbox account it gets automatically downloaded to the computers. Box.net only provides file synchronization for business and enterprise users.

If you need more than 5 GB of storage you will need to pay for it, and I recommend SugarSync, which provides 30 GB of storage for $49.99 per year. The minimum paid version from Box.net gets you 25 GB for $119 per year, and Dropbox provides 50 GB for $120 per year. Google actually provides the cheapest online storage with Google Docs providing 20 GB for $5 per year but unfortunately there are few, if any. smartphone apps that work directly with Google Docs.