If you click and drag a link that is in a frame to "pick it up," and then just drop it back in the browser window, you will view that link outside of the frame.
[Editor's note: Of course, the contextual menu works for this as well; control-click the link and select "Open Link in New Window." But if you don't want a new window, the drag/drop method described here is actually easier and faster!]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20030211064403973