InDesign CS3: Search Using GREP Expressions 

On the GREP tab of the InDesign Find/Change dialog box, you can construct GREP expressions to find alphanumeric strings and patterns in long documents or many open documents. You can enter the GREP metacharacters manually or choose them from the Special Characters For Search list. GREP searches are case-sensitive by default.

Adobe (2006). Articles>Editing>Regular Expressions>Adobe InDesign