GM has released a new SDK used to develop apps for its Next Generation Infotainment system. The NGI SDK provides app developers a virtual app building experience, accessible anywhere, that exposes 400 vehicle data points to the developer. Once built, developers can submit apps with a single click.
If you're interested in developing maps mashups using the Yahoo! Maps API but have not yet had the chance to use those APIs, you're in luck. There's now a very good book to show you the way, Yahoo! Maps Mashups by Charles Freedman.