It has long been possible to create configuration profiles for the iPhone and iPad, store those settings in a single file and deliver that file to devices via email or by download from a web server, by using the iPhone Configuration Utility.
This functionality has been incorporated into the release of Mac OS X Lion Server, in the Profile Manager feature.

Once the feature is enabled, select the link to "Open the Profile Manager". The configuration is performed via a web interface which you must log into with an administrative user account:

Once logged in you can edit the default configuration profile, or create additional profiles:

Editing a profile allows you to configure a wide range of features.

The General section allows you to enter a name for the profile and specify security settings - whether profiles may be uninstalled by users.

The Passcode section allows you to define security settings: whether a device requires a passcode to access it, how complex that passcode needs to be, how often it needs to be changed, whether passcodes can be re-used, how many attempts users may try to enter their passcode incorrectly, etc.

The Email section allows you to predefine POP and IMAP-based email account settings.

The Exchange section allows you to predefine Microsoft Exchange ActiveSync settings.

The LDAP section allows you to define directory access parameters.

The CardDAV section allows you to define address book access parameters.

The CalDAV section allows you to define calendar access parameters.

The Network section allows you to predefine wireless access point settings.

The VPN section allows you to predefine connection parameters for remote access accounts, including Juniper, Cisco, F5, as well as generic IPSec, PPTP and L2TP accounts.

The Certificate section allows you to add certificates to the configuration profile for installation onto the iOS clients.

The SCEP section allows you to define SCEP mobile device management server settings.

The Web Clips section allows you to package web URLs for installation onto iOS clients.

The Restrictions section allows you to disable specific functionality on the iOS clients including use of the camera the ability to install applications, use of Safari and YouTube and more.

The Subscribed Calendars section allows you to pre-subscribe users to shared CalDAV-based calendars.

The APN section allows you to predefine cellular connection settings.

Once all parameters have been configured, save the profile. Configured settings will be displayed in the list of available profiles:

Profiles can be accessed by users by browsing to the Lion server from their web browser - http://(Lion_Server)/mydevices/:

Or directly from their iPhone or iPad:

Once logged in, a list of available profiles will be displayed:

Which can be downloaded and installed onto the iOS device