In late January 2013, Microsoft launched its consumer-focused version of Office 2013, known as Office 365 Home Premium . On February 27, the company launched the updated business versions of its Microsoft-hosted Office 365 offerings.

Microsoft has added three new packages to its Office 365 line-up for businesses: Office 365 ProPlus, Office 365 Midsize and Office 365 Small Business Premium . These complement the existing Office 365 Small Business and Enterprise offerings, which Microsoft is updating with many of the latest new features and functions that it introduced late last year for the on-premises complements of the products in the suite. (Microsoft released to manufacturing Exchange Server 2013, SharePoint Server 2013 and Lync Server 2013 in October 2012.)

What does "launch" actually mean in the context of Office 365? Here's what Microsoft officials told me:

The three new SKUs -- Office 365 ProPlus, Midsize and Small Business Premium -- are available for purchase for the first time, as of today. (A free trial is available via this link .)

Brand new customers can start purchasing the latest versions of Office 365 for businesses which includes the updated Microsoft Lync Online, Exchange Online and SharePoint Online services

Existing customers with version of Office 365 that includes Office can start using the latest set of Office applications (Office 2013)

Existing Office 365 customers will continue to receive the updated versions of Lync Online, Exchange Online and SharePoint Online "throughout the year" -- seemingly through November 2013 -- a spokesperson confirmed. (Microsoft officials said late last year that some Office 365 enterprise users were getting the updated bits starting last fall.) Microsoft gives existing users a two-weeks heads up as to when Microsoft plans to transition them to the updated Office 365. Users can reschedule the assigned date, if need be.

Pricing for the new Office 365 business offerings is the same as what Microsoft's been telling partners it would be since late last year. Here's a slide from a deck the company supplied to partners outlining the pricing . (The top row reflects the Office 365 services pricing; the bottom row is the pricing for the equivalent on-premises SKUs.)

Read: ZDNet's Ed Bott goes hands-on with the new Office 365 business plans

Microsoft is holding an hour-long Webcast on February 27 to share more about the business SKUs of Office 365. Those interested need to register for the Webcast (the first of which starts at 11 am ET/8 am PT today).

Office 365 is Microsoft's competitor to Google Apps. It is a Microsoft-hosted suite that includes Exchange Online, SharePoint Online and Lync Online. Via various Office 365 offerings, Microsoft allows business users to install the Office client apps on up to five PCs and/or Macs locally. TechNet has more information on what's part of all the existing and new plans, ranging from Office 365 Small Business, to Office 365 Enterprise E and K.

Microsoft is not dicslosing how many Office 365 customers it currently has. The only customer numbers the Softies are sharing as part of today's Office 365 launch is that one in five of Microsoft’s enterprise customers now has the paid Office 365 service, up from one in seven a year ago. Officials also are saying that the number of small and medium sized businesses using Office 365 has also grown by 150 percent in the past 12 months.

Google, for its part, claims more than 5 million businesses use Google Apps.