delegate中，版本不同，回调方法不同。

//for ios version below 4.2
- (BOOL)application:(UIApplication *)application handleOpenURL:(NSURL *)url
{
	NSLog(@"url description: %@ \n",[url description]);
	if( [viewController.weibo handleOpenURL:url] )
		return TRUE;
	
	return TRUE;
}

//for ios version is or above 4.2
- (BOOL)application:(UIApplication *)application openURL:(NSURL *)url sourceApplication:(NSString *)sourceApplication annotation:(id)annotation
{
	NSLog(@"url description: %@ \n",[url description]);
	if( [viewController.weibo handleOpenURL:url] )
		return TRUE;
	
	return TRUE;
}