Thanks for the feedback.
@Goober: All valid points. The app is meant for the spectator of recreational tennis. I've had plenty of requests to make a tennis scoring app, so there must be at least a few people that will use it.
@tennismonkey: I hope to add a few statistics. I can only do a minimal amount with the info provided, but I can at least show % of points won.
@dufferok: Thanks. I write software at my day job, so learning Java and the Android framework wasn't too difficult. From start to having my first app on the market was probably 2 months of working on it evenings and weekends. Yes, I use Eclipse for the IDE.