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 Michael Webb:
mScrob is a Last.fm Scrobbling application.It's designed as companion to your iPhone's built in music player. When it's running and in the foreground it will:*Scrobble in realtime*Update your currently playing track on Last.fm.*Let you 'love' the current track.*Let you see the biography of the currently playing artist.When you run it again it will:* Scrobble the last play time for tracks you've play since it last ran. mScrob isn't a replacement for your iPhone music player, and it doesn't Scrobble in realtime when its in the background.