- (void)showDirections {
	if ([self.address length] == 0) return;
	//We create our link to the appDelegate
	ClubPlanetControllerAppDelegate * appDelegate = (ClubPlanetControllerAppDelegate *)[UIApplication sharedApplication].delegate;

	
	NSURL *myURL = [NSURL URLWithString:[NSString stringWithFormat:@"http://maps.google.com/maps?daddr==%@&saddr=%f,%f", [self.address stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding], [appDelegate.lat floatValue], [appDelegate.lon floatValue]]];
	[[UIApplication sharedApplication] openURL:myURL];
}

http://www.espinallab.com

Here is a peace of code from one of my project to show you how you to show directions on the Google Map application.

Show Directions on Google Map in the iPhone.

google

Objective C