>I'd like to give certain people in the organization the ability to query SQL Server tables in Excel
>
>However, I notice that when creating connections, the user can enter SQL Queries and from what I can see, those queries can alter data.
>In this installation, all Windows users of necessity have read/write access to SQL Server data
>Is there some way to restrict the Excel user to read only access?

sounds like they need more fine grained access rights/groups.