If you meet the requirements, you should consider joining the iOS Enterprise Program.
iOS Enterprise Program
You must be a company or organization with a DUNS number to apply.
Distributing Enterprise Apps for iOS 4 Devices
One highlight: You can wirelessly distribute your Apps to your customer.
iPhone Configuration Utility
iPhone Configuration Utility (IPCU) lets you easily create, maintain, encrypt, and install configuration profiles, track and install provisioning profiles and authorized applications, and capture device information including console logs.