Developing for mobile devices has been a high cost, low return proposition for many years, despite the hype around it. The latest generation of smartphones powered by the iPhone OS and Google’s Android provide a much simplified solution: just build Web applications. This gives you a one build for all devices approach, which can lower the cost. Even better, these high-end devices all offer ultra-modern browsers supporting advanced HTML, JavaScript, and CSS. In this article, learn how to build Asynchronous JavaScript and XML (Ajax)-heavy applications that take full advantage of the capabilities of modern smartphones. You will learn not only how to get the most out of these devices, but also how to deal with the subtle differences between them.
via IBM developerWorks: Create Ajax applications for the mobile Web.
Good tutorial. It starts out with a trivial Java app to create content, but any other server side tech, like PHP, could be used. The mobile portion relies on HTML 5 and AJAX in iPhone OS 3.x+ and Android 2.x+ browsers. You’ll need the most recent Adroid and iPhone SDKs to put this together.
This article provides a good starting point to start looking at how to build basic mobile apps.