“Gift App” from inside the app

Actually, you’ll want your URL to start with itms-appss: if you want it to open in the App Store app, where someone would actually gift an app. This feels more natural than Safari popping up.

// example app id for batman arkham city lockdown
#define APP_ID 459850726

NSString *GiftAppURL = [NSString stringWithFormat:@"itms-appss://buy.itunes.apple.com/WebObjects/MZFinance.woa/wa/giftSongsWizard?gift=1&salableAdamId=%d&productType=C&pricingParameter=STDQ&mt=8&ign-mscache=1",
                                APP_ID];

[[UIApplication sharedApplication] openURL:[NSURL URLWithString:GiftAppURL]];

APP_ID should obviously be defined to the Apple ID of your app.

Also worth noting, the URL is case sensitive.