Since a long time, I am busy to checkover between online services...to keep/store my data on the web... and to find an easy yet comprehensive solution to online file access and sharing between my various computers, included iPhone. After tried out Dropbox and ZumaDrive, I begun to use SugarSync and I may say that I decided to stay on this.
The service gives a free 2GB of online space, and it permits continous and automatic data sync, if you install it on your other computers with the same username. This may be your desktop and notebook, can be Mac, PC or/and some SmartPhones.. all combinations possible.. You may check some desired folders between computers, then you will be able them to be backed up / sync between your cyber space or/and between them, automatically.
One of the best features of the program, among others, as it plays mp3's by streaming on iPhone, instead of downloading... thanks to its iPhone App. The same applies to photos also.. I wished to recommend it since a long time, and after recently receiving an info mail, I am posting right now. For recommendations, they are giving +500 MB of extra to both parties. Below, is a referral link, if you register from there, both you and me will earn 500 MB of extra space. If you don't want, then you may register directly through the website.