On S60 2nd edition is possible to "install" applications by copying them to the right directories in the file system. This made possible for applications to be distributed preinstalled on memory cards so you just had to plug in a memory card and the application was immediately recognized and displayed in the shell.
It is not clear whether with S60 3rd edition and Symbian Signed this is still possible or not. My understanding is that there are new directories for application binaries, data files and so on and that is required for all SIS files to be signed. Can anyone confirm that it is still possible to copy the application binaries to the right directories on a MC, plug-in the MC and have your application show-up as installed.