sorry i just checked that link and it is now dead... doing a google search i found this... it may help you on your way
Here is the formula and must be array entered (Ctrl + Shift + Enter).
=VLOOKUP(A2,INDIRECT("'"&INDEX(MySheets,MATCH(1,--(COUNTIF(INDIRECT("'"&MySheets&"'!A2:A200"),A2)>0),0))&"'!A2:C200"),3,0)
Where: A2 is the look-up value
Where: MySheets is a named range consisting of a list of all the worksheet
you want to look up.
Where: A2:C200 is the lookup array of each sheet.
This will return the lookup value of column C that the lookup value finds on
whatever sheet, note the 3 just before the ,0) at the end of the formula.
You will need to adjust the ranges to suit your workbook.
This is what the formula would look like if you did not use a named range
for the worksheets but instead entered the worksheets names in the formula.
Much better to use a named range. Note that in this formula it returns the
value in Column B per the 2 at the end.
=VLOOKUP(A2,INDIRECT("'"&INDEX({"Sheet1";"Sheet2";"Sheet3";"Sheet4";"Sheet5";"Sheet6";"Sheet7";"Sheet8"},MATCH(1,--(COUNTIF(INDIRECT("'"&{"Sheet1";"Sheet2";"Sheet3";"Sheet4";"Sheet5";"Sheet6";"Sheet7";"Sheet8"}&"'!A2:A200"),A2)>0),0))&"'!A2:C200"),2,0)