It will be an app, where every day we will tell you about one best free app. But we don't know what iсon to choose. Please write your opinion about this for icons: 1. 2. 3. 4.
What does your interface look like? It should be consistent with the app itself. An icon should be clean and most of the time simple. at such a small size on the iphone / ipod touch the first is not the best choice. Out of these choices I'd most likely go with 3.
First - needs more contrast, #1 is the best of this set. Second - didn't a very similar app get rejected last week by Apple? You might want to investigate that before spending too much time with this...
I agree with chrisrushing, it's hard to say without knowing what it's going with. But if I had to pick one, probably 4, just as it is very clean and will look good and distinctive small.