SugarSync - online backup and synchronize

SugarSync website:
 https://www.sugarsync.com

The first 5GB is free. After install sugarsync, following the instruction, register an account, sign in your email to activate your account,  and select the folder you want to backup. The folder is synchronized in the storage in online cloud.  You can access to this folder where there is an Internet connection.

You can also can upload the files and access them via mobile phone. You can upload some files or put them in synchronized directory from your office and access them at home,  and vice verse.