The offer is aimed at large enterprises, most of whom now use Microsoft Office products, and counters Microsoft's Office Live and Online announcements this week, which made Word, Excel and other Office applications available on the Web and as a hosted software-as-a-service offering.
The enhancements to Google's Premier Edition customers will cost them nothing more than their existing £25/year/user. Office Online will be offered only to enterprises with more than 5,000 seats, with prices to be announced later.
A Microsoft spokesman said, "Customers who already own (Microsoft) licences with software assurance can receive credit for their existing licences if they choose to move to the Online services."
Postini, the networked communications security company that Google bought this year for £313m, will continue as a standalone company. It will also enhance security for GMail, Google Docs and other applications from the search company.
Peter Lorant, Postini's senior marketing director for the EMEA region, said GMail users can instantly set policies and filters for spam and viruses using Postini tools.
"Customers will also be able to archive and retrieve e-mails free for up to 90 days," Lorant said. Those who need to store e-mails for longer will have to pay for the service, which is already a Postini staple.
"This should help companies comply with many of their governing regulations," Lorant said. However Lorant could not say what conditions Google associated with service levels, quality of service or limitations of liability. "I have not been briefed on those, but I can tell you from a Postini position," he said.
In addition, Google has increased the amount of storage available to Premier Edition per user from 10Gb to 25Gb.
Lorant said the enhanced Premier Edition offering is live from today. Anyone wishing to test them has free access up to June 2008 provided they sign up before the end of 2007.