I've been keeping a close eye on the Android Device Dashboard. Google released it in December last year and I've found it to be a great way to find out the distribution of users across the various versions of the Android OS. This information makes it easier to target your app, determine whether supporting a legacy version is worth the trouble, whether you'll miss out on too many users by supporting a feature only available in the latest version etc. If only it was this easy on other platforms!
I looked at the numbers coming out of the Android Device Dashboard in a recent Geekzone blog post.
Anyone else been using the Android Device Dashboard or have suggestions for similar resources for other platforms?