Rather than try to get the throngs of immovable Outlook and Office users to switch to Gmail and Google Apps, it's going after Exchange with a new Apps Sync for Outlook plug-in that lets Outlook messages, contacts and calendar appointments sync with the $50-a-seat Premier Edition of Google Apps, the stuff businesses buy. Like Outlook syncs with Exchange.

That means IT can switch out the Exchange back end and move to Google servers without its users being any the wiser.

As Google's web site proclaims, it removes "another key barrier to enterprise adoption of Google Apps."

Users will be able to get their messages in both Outlook and Gmail and use Outlook rather than a browser to access Apps, a device aimed at wearing down their resistance.

At a press conference Tuesday in San Francisco David Girouard, the president of Google enterprise products, quoted Forrester Research as calculating that Google's hosted Gmail service is $11.85 a head cheaper a month for companies than Exchange.

Girouard claimed the Apps business is profitable and doing "hundreds of millions of dollars" with around 1.75 million companies using the widgetry. However, it's unclear whether they're all paying for it. There are reportedly 15 million users.

The plug-in, said to be a year in the making, only works on Windows.

Besides being part of the fee-based Apps service, the widgetry will be free to education and non-profits.