This post describes what order to apply updates for Office Web Apps installed on SharePoint Server 2010 or SharePoint Foundation 2010.

In a previous post on this blog, we talked about what order to apply Service Pack 1 and the June 2011 cumulative update for Office Web Apps running on-premises on SharePoint 2010.   If you haven’t applied those, start with that blog post first. 
If you have applied Service Pack 1 and the June 2011 cumulative update to your SharePoint Server 2010 farm or SharePoint Foundation 2010 environment that runs Office Web Apps, you will need to apply these additional updates in the order listed below to bring the server up-to-date: 

Note that IF there is a Service Pack 2 released for SharePoint 2010 and Office Web Apps running on SharePoint 2010 this blog post is moot.  You’d install Service Pack 1 and Service Pack 2 and then be done.  But we'll give you more specific information about that if that happens.

Hope this post helps!