Cell Link to workbook

I have a cell that is linked to another workbook. i run a macro and open up the workbook and it will update just fine. the problem i am having is that the workbook that i am linked to the file name changes everyday IE: today20091217.xls, then tomorrow will be "today 200091218.xls.
So how can i tell the link to change day to day?


Thanks

Yes the linked workbooks are in the same folder