Google has announced a new service that will push Gmail and calendar items to the native client software on BlackBerry devices.

The service will be included with the Premier and Education editions of Google Apps. End-users will find their Google messages pushed to the email client on their BlackBerry, and messages sent from their phones will appear to have come from their organisation's Google mail account.

They'll be able to access their organisation's Google address list from their phone, and to synchronise contacts and calendar items. The service is in beta and will be commercially available in July.

The service requires organisations to add a piece of software to their BlackBerry Enterprise Server (BES), and that software is available today only for the Microsoft Exchange version of BES. The software connects back to Google's mail servers, rather than the company's Exchange server, to synchronise mail, contacts and calendar items.

The service steps up Google's rivalry with Microsoft in the enterprise, but it does have some weaknesses.

Initially, calendar items can be synchronised only from the server to the user's phone. So if a user makes a new calendar entry on their BlackBerry, it won't be synched back to their online calendar. An upgrade that supports two-way synch should come by the end of the year, said Raju Gulabani, product management director for Google Apps.

In addition, the service will initially support only 250 users per BES. A BES can typically handle at least 500 users, sometimes many more. If an enterprise wants to support more than 250 Google Apps users it will have to use an additional BES.

Some functions of the beta version available today don't work smoothly with the BlackBerry. For example, calendar item reminders that appear in a user's inbox are formatted awkwardly, with what appear to be images that don't load properly.

In some areas, Google has had to work around the BlackBerry's limitations. For instance, the BlackBerry mail client only lets users search emails that arrived within the past month. To look for older messages, a user has to log into a separate Google Mobile App client on the phone.

Google thinks the new service will encourage more businesses to use Google Apps. Organisations use Google Apps because it can be cheaper and easier to maintain than on-premises systems such as Exchange or Lotus Notes, Gulabani said. Some end-users want the familiar experience of receiving email on their BlackBerry, however, hence Google is offering the new push service.

Google plans to update the service over time, by improving the end-user experience and increasing the number of users that can be supported on a BES server, Gulabani said.