Office Web Apps Server is a new Office server product that delivers browser-based versions of Word, PowerPoint, Excel, and OneNote. It compliments SharePoint 2013 very well, but if your unfamilair with it, there is a fair bit of learning to go with it.  Office Web Apps can be used on devices such as Windows Phones, iPhones, iPads, Windows 8 tablets, and Android devices.

OWA

Ddeploying OWA takes some complex planning.  Microsoft has deployed Office Web Apps Server by using a topology that can support 200,000 users and based on our performance tests, an Office Web Apps Server, with two Intel Xeon processors (8 cores), 8 GB of RAM, and a 60 GB hard disk, should support up to 10,000 users where most of the usage is viewing. A server that has a 16 core CPU and 16 GB of RAM should support up to 20,000 users. These results will vary depending on usage patterns and other factors such as network hardware.  Lots and lots of planning thoughts required, type of usage, volume of users, type of documents.  So it can be really confusing on top of the complexities of SharePoinjt 2013 generally.

OWA is a big ticket item for Microsoft to drive the success of SharePoint, Office generally and tools such as SkyDrive (it’s available for free on SkyDrive for example) and it is a critical component in your BYOD strategy.  Microsoft have thankfully released information to guide IT Pros on how to deploy and manage Office Web Apps on-premises with Office Web Apps Server.  It is a really comprehensive set of information and a great starter to understand the complexities of OWA and just how much you do really neded to think about.

Start here:  http://technet.microsoft.com/en-us/library/dn135237.aspx