In this Mac Dev Center article titled "Why You Should Lie to Google Maps" Matthew Russell shows Mac developers just how easy it is to integrate Google Maps in to Mac OS X applications.. as long as you lie a bit. :)
Here is a bit of the article:
..Fortunately for OS X developers, integrating Google Maps into your apps is cake. In fact, I almost decided not to even mention it -- but I couldn't resist because I thought the broader context of it all deserved some discussion.
Using WebKit, you can create a browser by writing only one line of code. Yes, ladies and gentlemen, it's true. Instead of reinventing the wheel here, however, take a look at the Mac DevCenter BYOB tutorial. When you build your own browser, you could go ahead and load up Google Maps right away, but it won't be a very friendly user experience. You'll be told that your browser isn't supported, and if you load the page anyway, you'll get slammed with intermittent messages like this one time and time again. Eventually, you'll risk losing your patience. Let's not go there.
"But Safari uses WebKit and it works fine on Google Maps. (..read the entire article..)