Yahoo! has just released the new maps API for AS 3.0.

The new Yahoo! Maps API is now entirely built in ActionScript 3.0. The Maps API now gives you an incredibly powerful map engine and the ability to create custom components, overlays and markers while consuming different webservices provided by Yahoo!, or your own. The YahooMap component is distributed as a SWC, to get started you need to include it into your build path using Flex Builder.

More info at Yahoo! Flash developer center.