Enable Office Web Application in SharePoint 2010

SharePoint 2010 support Office Web application, so we can use browser to browse office file in SharePoint. Before enable office web app, we need download and install.
1. Install Office Web Application
2. Run Configuration Wizard. after finish, system will open Central Administration. don't run Farm configure Wizard and closed wizard.
3. in Central Administration, Application Management -> Manage Service Application -> Secure Store Service, click "New" to add Excel Service ID in "Target Application ID" like 39235 (Excel)
4. Click Application Management -> Manage Service Application -> Excel Service Application ->Global Setting, set 39235 in "Application ID"
5. Now, when you right click excel file in library, you can see open by browser or client. if you want set browser is default, go to library setting -> advance setting, set browser is default.
6. on this time, you open Word or PowerPoint file, you will be get error message like "Word Web App cannot open this document for viewing because of an unexpected error". we need
7. Application Management -> Manage service on server to verify PowerPoint service and word viewing service is started.
8. If both application service are not in list, click "New" and then click "Word Viewing Service" and "Power Point Service Application".
9. in those application dialog box, in name, type those service name, in application pool, select "Use existing application pool" and then in the listbox, select "sharepoint web services default". then click "OK"
A. Now we can browse office file in browser.
B. came from : http://support.microsoft.com/kb/2028346