Given a font that is advertised as having multiple styles of numerals (text figures and lining numerals), presumably via OpenType, is there a way to use the alternative numeral styles in Mac OS X in general, or maybe within an app like Pages specifically?
Typographic features like this can normally only be used in a word processing app. You go to Format > Font > Show Fonts and click on the gear wheel and then select the Typography pane. There should be boxes to check for different styles of numerals, which will be applied to selected text in the app, as long as the app supports it. Try TextEdit first.