Real Time Charting

I'd like to update an excel chart in real time with data from a production
line. I can have data available at an OPC server and wondered if I could
have excel to get data directly from the OPC server.

We are using excel 2003 and I see that it has the facility for RTD and can
retrieve data from a COM automation server. Is an OPC server the same as a
COM automation server, or would I need to get an automation server to read
from the OPC server?

What is the best way of getting real time data from an OPC server into excel
in real time?

You can probably gather that I'm not that experienced in this area.

Thanks for any advice / guidance that you may be able to offer with this
project.

Joe