The Google Static Maps API (our Google Static Maps API Profile) is quite popular with developers looking for a relatively lightweight method of including Google Maps as rapidly-loading images on web sites. If you're not familiar with this API, it essentially allows you to add a custom Google Map (including markers and paths) as the source for an image element on a web page.
Do you know anyone with a car glovebox full of inked-up road maps? What a waste of paper (and ink!). Using Google Maps is, of course, the preferred method to mark up maps. One tool that makes it especially easy is Scribble Maps. And now it's testing "pro" features, a fee-based service with even more features.