GREP and Text Metacharacter Cheat Sheet
InDesign trainer extraordinaire and all-around nice guy Mike Witherell (owner of JetSet Communications in the D.C. area) has put together a handy one-page cheat sheet of all of the text and GREP metacharacters you can use in a Find/Change operation and made it available to any InDesign user. Here's a small excerpt:
(The Text column is blank if no text metacharacter exists for an entry.)
While I think you can discover most of these just by revealing the submenus to the right of the Find and Change fields in InDesign CS3, they're cumbersome to navigate through. Also, you can enter a lot of the text metacharacter ones in other places in InDesign, such as the "stop" character field when you're creating a nested style, and those places don't have the submenus. If you have Mike's chart tacked up next to the computer, you can see at a glance what's available.