NOTE: this is collected from some sites I can no longer find, so I can not take credit for this.
Longtime Mac users know that you can type characters with diacritical marks— for example, â, é, ì, ü, and ñ—by first typing the diacritic (which usually requires the use of the Option key) and then typing the letter. For example, to get ä, you press Option-U (to get the umlaut, or diaeresis) and then press A.
If you can’t remember all those key combos, you could use Mac OS X’s Keyboard Viewer to figure out which ones do what. But it can be a hassle to summon and then hide the Keyboard Viewer whenever you want a special character. Or you could try PopChar X (4.0/5.0; macworld.com/4659), the utility that lets you choose special characters from a drop-down menu; however, it’s probably overkill for most users.
An easier way is built right into Snow Leopard (Mac OS X 10.6). Launch System Preferences, open the Language & Text pane, and then open the Input Sources tab. In the list of input methods on the left, scroll down and enable U.S. International – PC. To make it easier to switch to this input method, choose Show Input Menu In Menu Bar.
That done, when you want to insert a character with a diacritic, choose U.S. International – PC from the Input menu on the menu bar and then create the character by typing a standard punctuation character followed by the letter:
- To Get an Acute Accent (´) Type ’ (apostrophe) plus the letter; for example, ’e gives you é.
- To Get an Accent Grave (`) Type ’ (accent grave, or backtick) plus the letter; for example, ’o gives you ò.
- To Get an Umlaut, or a diaeresis (¨) Type "(quotation mark) plus the letter; for example, "u gives you ü.
- To Get a Caret (ˆ) Type ^ plus the letter; for example, ^a gives you â.
- To Get a Tilde (˜) Type ~ plus the letter; for example, ~n gives you ñ.
To type a stand-alone diacritic followed by a vowel without creating a character with a diacritic on top of it, follow the diacritic with a space; that will disable the automatic replacement.