Office 2013 is Microsoft's latest desktop Office suite for Windows PC. Right now only the simplified web apps are available for Mac OS X, iOS, and Android.
You can install Office 2013 on one computer or device. If you want more mobility options or would like to install Office on more devices, consider reading All About Office 365. Office 2013 exists on your desktop and is cloud-integrated for sharing files or collaborating whereas Office 365 exists and operates in the cloud.
If you're ready to jump right in, you can still Install Office 2013 Preview for free. So far, it looks like your preview will stay active until mid-year 2013.
Programs and Features
Get to know new features for individual programs by checking out Office 2013 Programs: New Features and Image Galleries.
Office 2013 for Consumers, Households, Students
The core version of Office 2013 is Office Home & Student 2013. If you want more programs, look to the following business versions.
Office 2013 for Business
Office Home & Business 2013 - Intended for small businesses or those needing only core programs
Office Professional 2013 - Intended for larger businesses needing more program options
Office 2013 can be used on devices running Windows 7 or later. Unfortunately, it looks like Mac users will have to wait for the corresponding version, as has been typical for new versions of Office. Hopefully it will not be the usual wait of a year or so. Office 365, on the other, is currently compatible with Mac OS X.
Windows 8 is the new version of Microsoft’s operating system, which coincides with the development of Office 2013 and this entire productivity ecosystem. Some new Windows devices are built on Windows RT. For these devices, a specific version of Office 2013 will be necessary: Microsoft Office Home & Student 2013 RT.
For non-Windows devices, a trimmed-down alternative for Windows devices, the Microsoft Office Web Apps for Fall 2012 are the option you will want to investigate. Currently, full versions of Office 2013 are not officially on the horizon for iOS or Android, but fingers crossed!
The Bling: Apps, Not Add-ins
In Office 2013 programs, you can bring in additional functionality. Apps may perform tasks which are not standard or native to that application, so check out Add-ins and Apps in Microsoft Office.
New Office, New Ecosystem
Perhaps the biggest overarching feature is the new integrated environment Microsoft Office is now part of. Often referred to as an ecosystem, it spans multiple devices and the SkyDrive cloud environment. While Office 365 offers more extras in that ecosystem, both allow sharing via SkyDrive.
Your Alternative to Office 2013 Desktop: Subscriptions and Office 365
With all that connectivity comes a new way for buying Office. Meet subscription pricing, the new trend for accessing productivity tools in the cloud and across multiple devices.
Buying a Desktop Version of Office 2013
While Microsoft wants you fully integrated into its cloud-based productivity ecosystem by switching to Office 365, the software company is still offering the desktop, out-of-box versions listed above. Click through the version links for consumer or business suites to connect with details, system requirements, and where to buy Office 2013.
Upgrading to Office 2013
Some upgrade deals are available for those who have bought an older version within certain time frames.
Please let me know if you have additional questions!