With 237 (and counting) almost universally glowing reviews, iFooty is one app that's scoring well on the UK iPhone App Store, riding high on the Top 25 Free apps list.
What it does it pretty simple -- aggregating football league data and news articles from a variety of BBC sources -- but it does it very well and with great style. As many of the user reviews [App Store link] point out, it's one of those apps that's really, genuinely, use-it-six-times-a-day useful.
I should point out, for the vast American majority of readers on this site, that when I say "football," I mean it in the UK sense of the word. I suspect you know it better as soccer. But over here it's football, or just footy, and iFooty's comprehensive coverage of the uppermost football leagues in England (Premier League, Championship, League One, League Two) and Scotland (Premier League) offers something for many millions of fans. And, better yet, it does so for free.