Not too many icebergs on the southern shores of Alaska in August (unless you take a boat cruise out to a glacier), and polar bears don't usually venture south of the Brooks Range (a good 200 miles north of Fairbanks).

A good site with comprehensive listings of activities (aside from Wikitravel, which is good but is user-updated and is occasionally missing some things) is http://www.alaska.org. It's run by some people I know and isn't too influenced by paid listings (as far as I know; that's The Milepost's downfall), and they do make good value judgments and only post the stuff that's worthwhile.