I submitted smartSCORECARD to the Apple iPhone Web App site last week. It debuted as the Featured Web App for "All Categories" and is still currently the Featured Web App for "Sports." It lets you and up to three buddies keep score on the golf course. You must be an oobgolf.com member to use it (membership is free)--it leverages course data from oobgolf.com and stores your live scores on the oobgolf.com website.
See:
Apple - Web apps - smartSCORECARD
Yes, it's not a native app, it's a web app. But you'll only need an Internet connection near the clubhouse (when you start and end your round).
thanks, Chuck