Data backup and sync

Required: To create an online service that will provide data backup and sync service between mobile and computee devices. The following milestones will be used: Design Implementation Testing Go live. Objective. To create a cloud based service which will allow users to keep their data backed up and in sync across multiple devices per user. A three tier model will be prefered, with a client, application server and a database. The basic free service will allow a user to backup his Address book and Calender for one device free for a period to be determined by the administrator. In this case, a user account will be tied to only one device at a time. A paid service will exist for which the payment will depend on the number of devices tied to the account and the contents that can be synced. An existing platform like funambol would be prefered for this service, or any other platform that is good reputation.