I haven't encountered too many uses of Google maps in other web pages. If you're interested in where cell towers in your area are, here's an interesting site that has that data and shows it visually using Google Maps.

The coverage and dead spots portions of the web site don't see all that useful as they rely on user comments (I couldn't see that there was a good filtering search system that worked very well). Some of the comments included: "I didn't get any reception on the second story of my office building" and "my city has terrible coverage with no end in sight ... I'm finally going to switch carriers after five years." Yeah, that helps.