With the release of Ice Cream Sandwich looming on the horizon, Android lead tech writer Scott Main has taken some time to talk to developers about how to get Honeycomb-only apps ready for the smaller screen. When ICS is released, and going forward from that point, the Android code for phones and tablets will be the same, just displayed differently based on screen size. Because of the different devices available, tools and methods were built into Android to handle how things are shown to the user. Using fragments and the action bar, apps can be built that show information in one big view, or split into separate screens for devices with lower resolutions.
Scott goes over all the tecnical aspects well at the Android Developers blog (see the source link below), and gives developers a lot of ideason how to get started when the ICS SDK finally arrives. What you can do right now if you've developed and app for SDK 11 or higher is make sure it's only available for large screen devices in the Android Market, at least until you can implement some of the new changes coming with ICS. Now all that's missing is the update, which should be pretty soon we think.
Source: Android Developers