Gary Little, a realtor in Sechelt town, British Columbia, created an “interactive map application that shows the locations of all MLS-listed properties for sale on Sunshine Coast. I recently rewrote & simplified so it works on iPhone and Android phones. This meant migrating to V3 Maps API. One problem I faced was that there was no easy way to create & display custom info window when a property's marker was clicked. To solve this problem I created a class called “InfoBox”. You use it just as you would a google.maps.InfoWindow but it supports several additional properties for controlling the styling of box. You can also use an InfoBox as a map label, so it's useful for identifying landmarks that aren’t on base map. InfoBox is now part of the google-maps-utility-library-v3,” writes Gary.
More info: InfoBox