I have many apps, i want to organize my 150 apps in folders (but not on the home screen). Any suggestions how to do this properly?
This isn't a difficult thing to do. You just need to use a 3rd party launcher which is highly customizable. Like Nova or Apex Launcher.
You could also give "Aviate Launcher" by YAHOO a go which automatically makes a few "categories" as your home screens. But it's nothing like the usual launcher we use so liking it or not will be upto you.