Thanks for this awesome post. This is seemingly the only method that currently works without using undocumented methods.

I have this code working, however when I call the function again, to change the UserAgent to something else, UIWebView's do not update. In order to successfully update the UserAgent I need to remove/release the UIWebView and alloc/show it again.

-(void)setUserAgent:(NSString*)userAgent {
NSDictionary *userAgentReplacement = [[NSDictionary alloc] initWithObjectsAndKeys:userAgent, @"UserAgent", nil];
[[NSUserDefaults standardUserDefaults] registerDefaults:userAgentReplacement];

//SHOULDN'T HAVE TO DO THIS
//get webView values then release
CGRect webFrame = webView.frame;
NSURLRequest *webRequest = [[webView request] retain];
[webView removeFromSuperview];
[webView release];

//allow webview and add to screen again
webView = [[UIWebView alloc] initWithFrame:webFrame];
[webView setScalesPageToFit:TRUE];
[webView setDelegate:self];
[self.view addSubview:webView];
}

This is mostly OK however it causes the UIWebView to lose all history. Is there any way to update the UserAgent without having to create a new UIWebView in order to have it take effect?

Thanks again