I made an application for the iphone in Xcode, but as a result of recent developments, I now need to make it into a web application.
I know that Dashcode creates web applications suitable for the iphone. Can I somehow import my Xcode project into Dashcode? Or can I use Xcode to make it into web app without completely re-writing the application?
Not easily. Neither Xcode nor Dashcode will help you translate your interface or your Objective-C code over to HTML and JavaScript.
If you have a lot of Objective-C code that you need to keep using, you might be able to get some mileage out of Objective-J.
You may be able to salvage some logic, but for the most part you are looking at a complete rebuild. If you can find a web app framework that uses objective-c you may be able to recover some classes that extend Foundation classes.
Like Ryan said, you might be able to salvage some parts of the code, but Xcode is not and will not export all the formats they use into HTML. Also, some of the HTML styles in Dashcode can't run certain processes that your app from Dashcode might need.