Already it has overtaken Symbian - for a long while front runner as far as smartphone platforms are concerned.
Porting applications from one platform to another is not simply a matter of copy & paste. Android is fundamentally different to iOS (iPhone). So the application will need to be revamped to cater for a different environment.
Luckily Google has made development for Android easy. E.g. there is the programming environment - which is Java and XML. Both standard languages (as opposed to Objective-C which is more or less used only by Apple).
I'll start work on the Android version within the next couple of days. I anticipate it'll take me the summer to get it done. So this year should see iStayHealthy both on Android and iOS platforms.