In Excel 2010, you can still use the Replace function to replace the worksheet name in a formula linked to a different workbook. Here's how:
[list=1][*] Select the cell containing the formula you want to update.[*] Press Ctrl + H to open the Find and Replace dialog box.[*] In the "Find what" field, enter the old worksheet name (e.g. "Weekly Sales").[*] In the "Replace with" field, enter the new worksheet name (e.g. "Weekly Sales").[*] Click the "Options" button to expand the dialog box.[*] In the "Within" field, select "Workbook".[*] Click "Replace All" to replace all instances of the old worksheet name with the new one.

Note that if the worksheet name is part of a longer string (e.g. "='M:\ACCOUNTING\Mike\2010 Sales\6 - Period 2010\06152010\[3 - BoulderWE061510.xls]Weekly Sales'!$E$46"), you'll need to be careful not to replace any other parts of the string that might contain the same characters. In this case, you could try using wildcards in the "Find what" field to match only the worksheet name (e.g. "*Weekly Sales*").