I have documents saved in a document library in Sharepoint 2010.  I want to be able to have multiple users edit a Microsoft Excel document in Excel by opening a document from this Sharepoint document library.  I am able to change my settings to allow multiple users to view and edit Excel documents in the browser.  But I am not able to have multiple users edit the same document at the same time in Excel itself.  Users are required to either wait until the current user finishes using the document and/or check out the document in order to make changes.  Is there a solution to enable multiple users to edit an Excel document at the same time from a Sharepoint library?  Thanks.

check the similar post 

http://social.technet.microsoft.com/Forums/en-US/932cad22-05e8-404f-ab0f-a6415c042582/editing-excel-files-simultaneously-saved-in-sharepoint-2010?forum=sharepointadminprevious

Unfortunately, co-authoring is not supported for the Excel 2010 client application in SharePoint Server 2010.

Check the following article.

http://technet.microsoft.com/en-us/library/ff718249%28v=office.14%29.aspx

"The Excel 2010 client application does not support co-authoring workbooks in SharePoint Server 2010. Co-authoring workbooks in SharePoint is supported by using the Microsoft Excel Web App, included with Office Web Apps. "

you can have co-authoring using Office web Apps

OP mentioned that he is already doing that.

" I am able to change my settings to allow multiple users to view and edit Excel documents in the browser. "