Telerik's Icenium for Android and iOS mobile development
Mark Riffey recently mentioned Telerik's Icenium, a cloud-based development tool for both iOS and Android development that leverages JavaScript and HTML5. There's a desktop IDE for Windows developers and a browser-based UI for other platforms. Your code lives in the cloud (Rackspace, reportedly). Apps are distributed through their respective app stores.
Icenium uses Telerik's Kendo UI, which lets you use one code base and create native user interfaces on multiple platforms. There's also something called LiveSync, which makes it possible to have multiple different test devices running and all syncing in real time to changes made via the development environment.