Redmond (WA) – Microsoft today continued its online ping-pong game with Google and launched “Microsoft Online Services for Businesses of All Sizes” in the growing software-as-a-service (SAAS) arena. A trial of the beta is available for free, but Microsoft will be charging subscription fees when the service goes online in the second half of the year.

The company is promoting Microsoft Online Services (MOS) as a key part of its newly created “software plus services” strategy, is an attempt to convince users to use its software services. Fee-based online applications will include services such as Exchange Online, Office SharePoint Online and Office Live Meeting- all of which are currently in beta.

“The combination of software plus services gives customers advanced choice and flexibility in how they access and manage software,” co-founder and chairman Bill Gates said. “With Microsoft Online Services, businesses can deploy software as a subscription service, from servers they manage on-site, or a combination of the two, depending on their specific needs. In the future, customers and partners should expect to see this kind of choice and flexibility for all of Microsoft’s software and server products.”

In contrast to Google, there is no such thing as a free ride on MOS. New customers and customers who do not participate in the firm’s Software Assurance program will have to can purchase Microsoft Online Services as a per-user subscription. Existing customers with Software Assurance on their Microsoft Client Access Licenses can purchase a user subscription “at a discount”.