Open Workbook using URL instead of network path

I have been using Workbooks.Open "path....." to open a workbook, but now I
need to be able to open a workbook in a portal database. Can anyone tell me
how to go about doing this?

The old way: Workbooks.Open
"P:\MODULE\Area\REPORTS\ProductionData\PRODdata0506.xls"

New URL:
"http://company/site/area/Production%20Data/PRODdata2005-2006.xls"

Thanks in Advance,
Raul