The NPR Music app may not appear in the iPad apps results when you search in the App Store right now. It can take up to 24 hours for the app to fully make its way through Apple's system. The app should appear as an iPhone app, however.
iPad users who have never installed the NPR Music for iPhone app on their iPad should visit the iTunes page linked below, or search for NPR Music in the store. If you see the iPad version, go ahead and install that. If you only see NPR Music listed as an iPhone app that's okay. Try to install it. It should run as the iPad version.
If you already had the NPR Music for iPhone app installed on your iPad, you should see an update available in the updates panel of the App Store. Use that to update your existing app, which should convert you to the new iPad version.
If you keep seeing the iPhone version, quit the App Store and then re-launch it, then check for an update available for the NPR Music app in the App Store Update screen. Update, and it should convert you to the iPad version.
If all else fails, check back later in the day for an update to the app. Unfortunately there's no way for us to speed up the process of getting the app pushed through Apple's systems.
Get the NPR Music app.