Clear Android Default Applications
Got new Android handset and wondering how to change the change the default apps? The operating system offers you a way to change the default app to your own favorite one like media player, browser or texting app.
Menu > Settings > Applications > Manage Applications
and locate the app whose default you want to change. If you want to go back to your stock launcher after using ADWLauncher, find the ADWLauncher app on the list and click on it.
Now move down a bit and tap on the “clear defaults” button and you are done. Next time you do an action that you had set that app as the default for, Android will pop up a notification offering a list of apps that can be set as the default for that action.
Select the “Use by default” check box, make your choice, and you are done.