One wonderful thing on a Mac is self-contained applications. You don`t have a bunch of misc dlls and system files that applications require. This allows you to drag & drop to install things.
The problem with dragging & dropping an application into the applications folder is that the permissions are setup for the user that dropped the application, but other users then can`t use it.
ChangePermissions is a free and AppleScript based droplet which will allow you to just drop the application (or other files/folders) so they can access the files as well.
NOTE: You will have to open the droplet in AppleScript Editor to add and administrator account and password.
WARNING: An administrator username & password has to be hard-coded into this droplet so it could be a security concern. Only give to completely trusted users (also try saving as run-only).