Using Windows Azure storage for backup

You would probably be better off using the Azure Online Backup service rather than trying to roll your own. There is an agent that you install on each computer and it integrates with the Windows backup console.

http://www.windowsazure.com/en-us/services/backup/

To answer your questions about Azure Online Backup:

1. There is an agent

2. This depends on your internet connection, not Microsoft's

3. It transfers over SSL, if that's what you mean. "Is it secure" isn't really a question, since it means different things to different people.