NewInstance

I used to create launchers in Linux for command line applications, to place on the desktop or in some bar. On Linux, that is as easy as specifying the launcher command or bash script, tell if you want run it in a console or not, and specify an icon. On OSX (...) read this article.
If you are launching a script and you want AppleScript to terminate, you have to redirect stdout/stderr to /dev/null; example:

do shell script "~/bin/myscript > /dev/null 2>&1 &"