iPhone development tools that work the way you do
You don't need to master Cocoa and Objective C to create killer iPhone apps. Rhomobile, PhoneGap, Appcelerator, and Ansca tools leverage standard Web technologies and still tap native featuresFollow @peterwayner
Keeping the client as light as possible makes sense in the resource-challenged environment where every parse sucks away precious battery life, but it undermines one of the features. If you have pre-existing Ruby code that uses XML, you'll need to work a bit harder to port it to the iPhone. It's not always simple. You might be required to integrate an XML parser or strip out XML formatting code.
The Rhomobile tools are just the beginning. Rhomobile is also building RhoHub, a hosted development environment that lets you create smartphone apps on the Web.
The Rhodes framework is a great tool for Ruby programmers, and it may even be a good option for someone who isn't familar with Ruby. While I encountered a number of rough spots, the integrated server mechanism can be tempting enough to force someone to learn Ruby. And though the cross-platform promises are just meant to ease porting to the various smartphones, you should be able to move your applications to the general Web with little trouble.
Rhomobile is gradually emerging out of the early beta-like stage and setting prices. As version 1.2 is released, the company will set a firm price for creating an application with Rhodes and a price for linking it to a RhoSync server.
The PhoneGap open source project started as a bit of a hack by some programmers at Nitobi, but it quickly attracted enough attention to make it a real competitor. The folks at Nitobi are working on both enhancing the open source version and finding a way to add commercial features.