Migrating a lot of users

Good Afternoon,

At my company we've recently negotiated a new phone contract for our staff.

We've got some 150 iphone users who are all getting upgraded handsets.

My question is what services or applications are out there that will ease the transfer of all this user data, settings, etc.?

At present the devices are effectively unmanaged and itunes accounts are usually set up by each individual user.

Any suggestions would be welcome as I don't much fancy doing backup and restores of some 150 phones!