Developers have flocked to Apple's iPhone SDK, but there is a significant barrier to entry: knowledge of Objective-C, the programming language that is used to build native iPhone apps.
Fortunately, cooking up a hot iPhone app doesn't require you to get too geeky. Developers who don't know Objective-C, or who don't want to learn yet another programming language, can build native iPhone apps using these five tools.
Price: $99 ("special introductory price")
If your programming language of choice is Ruby, Rhodes may be just what you're looking for. It's an open source framework for building native mobile applications, including native iPhone apps, that relies on HTML and Ruby.
Price: free for open sourced apps, $500 per commercial app
The iPhone may not support Flash, but that doesn't mean that you won't soon be able to build native iPhone apps using it. Adobe Flash CS5, which is currently in private beta, will include a new feature called Packager for iPhone. As the name implies, the Packager will let Flash developers package their Flash projects for the iPhone.
Price: To Be Announced