Does anybody know where I could find WinForms controls that mimic those on the iPhone? I am interested in doing some iPhone prototyping using Visual Studio and it would be handy if I could make the controls look like the native iPhone controls.
I know that I could just use Interface Builder on a Mac, but I do not want to do this. I just want to play around with various ideas and I will be much faster in Visual Studio.
Since the iPhone's UIKit controls are very likely highly protected by Apple's trademark and copyrights, I wouldn't expect to find alternative implementations. Since any iPhone development will eventually require using Interface Builder, it's worth repeating what many others have said: use the right tool for the job. Learn Interface Builder (it won't take long) and quit trying to shoehorn iPhone development into the Windows tooling.
As I pointed out here, an alternative to doing this in WinForms might be to mock up your interface using the Briefs framework. Briefs lets you use images of any kind to represent screens of your application, and assign interaction behaviors to areas of the images. You can generate a fully functional iPhone application from this for quick testing of your user interface.
There are a number of iPhone UI wireframe elements for Photoshop and other illustration applications out there, so it's pretty easy to draw up your prototype interfaces.
If you are interested in doing iPhone apps in C#/VB.NET, MonoTouch is the way to go
To me it is weird to emulate iPhone UI in WinForms as they are two worlds apart.
Balsamiq Mockups has some iPhone-like controls, and you get a mock up done faster than in Visual Studio.
I've had a look around for windows forms iPhone controls for mocking and positioning items and couldn't find any. However it's quite easy to do yourself with a few screenshots from the iPhone Simulator. Below is what I've done - I'll update with a download link to the project a bit later.
As mentioned Apple probably won't like, nor let you release a product using their UI style. However for mocking there is nothing to stop you doing it in Visual Studio - they still get their $99 and appstore cut.
I use Visual Studio as I do XIB-less Monotouch development in it, and want to avoid switching back and forth. For XIB-less apps, designing with interface Builder isn't much faster in my view - but that's a Monotouch-centric viewpoint.