Running script or query on multiple SQL Instances at a same time (simultaneously) offers professionals great flexibility and allows saving time. Many third party tools offered this capability from long time and now it is a native feature of SQL 2008.
Follow below steps to use this feature:
1. Open SQL Server 2008 Management Studio and create a server group with adding the registered SQL servers where you want to run the query simultaneously.
2. Right click on the group name and click query to open a session which will run the query on all the servers at a same time. (Please refer to below picture for details)
3. Now once the new window opens, execute your query and it will be executed on all the SQL servers which belongs to that group. (Please refer to below picture for details)