As I understand application with new maps SDK v2 can be installed only on devices with Google Play services APK.
And v1 keys will not be available after 3/2013, so does it means I can't build today map application which runs on most of Android devices?
As I understand application with new maps SDK v2 can be installed only on devices with Google Play services APK.
The app can be installed on whatever devices you want. Maps V2 will only work on devices with the Play Services Framework APK. This should already exist on most Android 3.0+ devices and should be downloadable to many Android 2.2/2.3 devices.
so does it means I can't build today map application wich runs on most of android devices?
First, Maps V1 works on most Android devices. The fact that you cannot get new API keys starting on 3 March 2013 does not mean that you cannot use Maps V1. Simply make sure that you have a long-lived debug keystore, that you have Maps V1 API keys for that keystore and your production keystore, and that you have a decent backup regimen.
Second, Maps V2 should work on "most Android devices", though dealing with devices that do not presently have the Play Services Framework (but could download it from the Play Store) is a bit annoying.
Third, there are other mapping solutions available, such as OpenStreetMap with OSMDroid, that can run on just about anything.