Update 9/27: This post relates to PhoneGap 2.0. 2.1 appears to have fixed a number of iOS 6 compatibility issues, and I recommend upgrading.
Today I upgraded my Xcode to 4.5, which now builds apps against the iOS 6 sdk. This included many breakages to my projects that I had to fix, and a couple to my apps themselves.
The two biggest problems were:
Apple Mach-O Linker Error. Linker command failed with exit code 1. File is universal but does not contain a(n) armv7s slice.
To Fix problem 1, I simply had to navigate to Project > Build Settings and change
Build Active Architecture Only to "Yes".
To Fix problem 2, I had to change some of the PhoneGap base code. I found the solution here.
In Classes > AppDelegate.m change the line:
self.window.rootViewController = self.viewController;
and in Classes > MainViewController.m, add the line:
self.webView.frame = CGRectMake ( 0, 20, self.view.frame.size.width, self.view.frame.size.height-20);
That's it - this makes the WebView inherit from the root view controller instead of a subview, and the additional line allows the webview frame to load without being cut off by the status bar.
Next: iOS 6 Assistive Touch