Synchronica has shipped a trial version of its previously-announced service that lets iPhone users access and synchronise with Microsoft Exchange.

Available now as a 60-day free trial, Mobile Gateway 3.0 offers mobile synchronization between Microsoft Exchange and the native email client of the iPhone.

The hosted service offers enterprise users the facility to send and receive corporate email using an iPhone, without requiring they install software on the device or behind the corporate firewall.

As it ships, the built-in email client of the iPhone only supports Microsoft Exchange via direct IMAP/SMTP connections - a feature that is often blocked by corporate firewalls due to security concerns.

Synchronica is offering a secure gateway that uses Microsoft's Outlook Web Access (OWA) to retrieve email from the Exchange server.

The developer describes Mobile Gateway as a "perfect companion to iTunes," adding: "While iTunes synchronizes calendar and contacts with Microsoft Outlook, Mobile Gateway keeps iPhone users connected to their corporate email once they have left the office. It provides tight integration between the iPhone and Microsoft Exchange and automatically delivers emails to the built-in email application of the iPhone, including support for folders and attachments."

Replies and new messages are relayed back to the corporate Exchange server and appear in the Sent Items folder in Outlook when the user comes back to the office.

Signing up for the service simply requires that users register their iPhones with Synchronica's Mobile Gateway. They can then start to send and receive wireless email immediately - no software need be installed on the device or corporate network.

Data is protected during synchronization by encrypted IMAP/SMTP connections to the iPhone and secure HTTPS connections to Microsoft Exchange.