Hey I found a workaround to all this coding.
First, set your workflow to run every time a item is changed.
Secondly, add a temporary text type column to the list that you want to run multiple updates on.
Thirdly, in Internet Explorer switch to a datasheet view and make sure to include the new field you just created to the data field view.
Fourthly, go to the first item in your list and enter any string into the new temporary field you just created. Before you commit the changes, highlight the whole column, right click and select fill down. Then change the view back to the standard view (SharePoint will alert you that changes are being made to the list so you should stick around).The workflow will run for all the changes you just made.
All set you have updated multiple items with the results pushed by your workflow.