SkyDrive is one of the most popular cloud storage service along with Dropbox. The good thing about SkyDrive is that it offers more free space than Dropbox and is also available across all mobile platforms. SkyDrive has now even better on iOS with the ability to automatically backup and upload photos from the camera roll into the cloud storage. This feature is already available on SkyDrive for Windows Phone and now been extended to iOS.
So now all your photos taken on your iPhone or iPad can be accessed online from SkyDrive or can be synced to the desktop using the desktop application.
And like with any other service, you can choose whether you want to upload photos using only Wi-Fi connection or use the cellular connection. Using the cellular connection will obviously incur more charges in case you are having a limited plan on your phone. SkyDrive web interface is also pretty good with lots of options including sharing to Facebook.
You can update the app on your iOS to get the new features.