Got this answer on the net. Is it the right way?
The delay that you are seeing is the Android operating system "opening" the home screen application after it has been stopped. Unlike most other phone platforms, the Android home screen is nothing more than an application (like Messaging or Email) which is triggered when you press the home button (or back button enough).
The Android OS will often stop applications which are running in the background but not being used in order to free up more resources for the ones you are currently using. If you spend an extended amount of time within an application such as a game or Messaging, the Android OS might stop the home screen activity to allow the current application to function better. When you press the home screen button to exit, it has to start up the home screen from scratch. The delay you see is the home screen starting up from a completely stopped state, much like the delay you would see when opening a large application for the first time since booting.
There is no (easy) way to prevent this from happening and in reality you shouldn't. The Android OS is built on a very robust platform that has been designed to handle resources much better than a human being. This is also the reasoning behind not using a task killer. The OS knows best.
To mitigate the problem, an alternative home screen might be worth a try. Three popular ones are*LauncherPro,ADW.Launcher, and*Zeam. Reducing the number of applications that run in the background will also help free up resources and allow the home application to stay loaded for much longer. Applications like Facebook, Twitter, Flickr, and most multiplayer games all keep services running in the background which consume resources.
Posted via the Android Central App