Вот и все с GCD::)
NSURL *urlObj = [NSURL URLWithString:url];
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0);
dispatch_async(queue, ^{
NSURLRequest *request = [NSURLRequest requestWithURL:urlObj];
[webViewObj loadRequest:request];
dispatch_sync(dispatch_get_main_queue(), ^{
[webViewObj release];
});
});
Надеюсь, это поможет.