Symbols in Pages

Pages and virtually every other MacOS X application has a Edit/Special Characters... menu selection.

A bit of additional information: My guess is that you are looking for Microsoft style Insert/Symbol... menu selection. This is unusual for traditional Macintosh applications. Here, we prefer to type-in characters using the keyboard whenever we can. With the enormous number of characters available, the Keyboard Viewer and Character Palette come-in really handy.