/* HEADER FILE */
#import <UIKit/UIKit.h>

@interface ViewController : UIViewController {
	IBOutlet UIClassName *variableName;
}

@property (nonatomic, retain) UIClassName *variableName;

@end


/* IMPLEMENTATION FILE */
#import "ViewController.h"

@implementation ViewController

@synthesize variableName;

- (void)dealloc {
    [variableName release];
    [super dealloc];
}

@end

Important: After adding the Header File Code below, save then jump back to Interface Builder and Ctrl+Click on File's Owner and assign the Outlet to the correct component under View.

Linking Interface Builder to XCode

Objective C