Update Feb. 2016: Nero BackItUp is being discontinued. Current users have until May 5, 2016 to get their data off their servers, when it will be deleted. I recommend users check out G Cloud Backup or IDrive as an alternative (both support mobile backup).
Nero BackItUp is software that can backup your PC, Android, iOS, and Windows Phone. It can store your backups either in the cloud, on local media, or both. It’s also free to use, with up to 5GB of cloud storage included.