The aim of this was to allow me to:

  1. Migrate batches of On-premise mailboxes to Exchange online in a Hybrid deployment by using a centralized location.
  2. Get some idea of how long the moves will take,
  3. Keep track of the mailbox moves,
  4. License the mailboxes,
  5. Suspend moves if required and resume them when you need to.
  6. Report on all licenses assigned.

This tool is in no way an Official Microsoft Office 365 Tool and not maintained by Microsoft, it is essentiall maintained by myself.

For more information around this tool please read: http://blogs.technet.com/b/mikehall/archive/2013/06/25/office-365-hybrid-mailbox-migration-management.aspx