Using the space bar as a shortcut in finder to preview audio files
Looks like Quick View is only available for Mac OS X 10.5 and later.

Bottom line, download 10.5 and the spacebar Quick Look will work.

As a side note, if you're looking for other shortcuts that might be missing from OS 10.4, there's a shortcut creator (on steroids) that's free, and it's called BetterTouchTool. Go here to download it (http://www.bettertouchtool.net). Just remember you have to have 10.8 or later for it work.

You won't regret it.