The download button opens the iTunes App Store, where you
may continue the download process. You must have iTunes installed with an
active iTunes account in order to download and install the software. This
download may not be available in some countries.
From EkcoApps:
UrSampler gives you a simple way to play sounds from your iPad. This app is great for mobile DJ's that just want to have their favorite party samples quickly accessible. The app also provides a portrait or landscape mode for DJ setup compatibility.