I have an Excel spreadsheet on my portal (SharePoint 2007). I have a site with
an "Excel Web Access" web part that displays "Chart 1" from this spreadsheet. I
need the chart to update when the spreadsheet changes. The only way I can do
this is to select the "Reload Worksheet" option from the web part tool bar. I
want the reload to happen when the read-only user browses the page.

Or - is there an Excel update service that runs on an interval that would do
this?