Google has launched Google Apps Premier Edition, providing online applications for business that will hit Microsoft's bottom line hard.

Users will now have access to Google's online document and spreadsheet applications, shared calendar functions, instant messaging and a BlackBerry client, as well as full support for existing company APIs for integration.

The package costs $50 per user, and non-US customers will pay the equivalent price based on exchange rates.

Google has not ruled out adding additional functions, such as presentation software, at some point in the future, and stated that it does not plan to charge more for different packages.

"We do not have three to five year product cycles," said Robert Whiteside, head of enterprise sales at Google UK.

"These are not the only applications we will bring out. What they are and when they come out will depend on what our users want."

The move is expected to hit Microsoft hard, since the company makes a sizeable proportion of its profits from the Office application suite that Google Apps directly challenges.

Existing personal users of Google's applications will not be charged for the applications, but businesses are being targeted and already some big name clients have signed up.

"Procter & Gamble Global Business Services has enrolled as a charter enterprise customer of Google Apps," said Procter & Gamble GBS director Laurie Heltsley.

"P&G will work closely with Google in shaping enterprise characteristics and requirements for these popular tools."

Each user gets 10GB of personal storage, and companies get a 99.9 per cent guarantee of service uptime and 24/7 support.