The easiest way to print bar codes from an Excel spreadsheet would be
to use a bar code ActiveX control that is designed specifically for
this purpose.
With a bar code ActiveX control, you just drop the control into a
spreadsheet, bind it to a cell containing the data that you want in
the bar code using the "LinkCell" property of the ActiveX control and
when you print your spreadsheet, the bar codes get printed
automatically for you.
The best bar code ActiveX control available is from TAL Technologies.
Visit the following URL for more information:
http://www.taltech.com/TALtech_web/products/activex_barcodes.html
You can download a demo version of the TAL Bar Code ActiveX control
from the above web page. The demo comes with a sample Excel
spreadsheet that demonstrates how to use the control in Excel.