Here's a simple defun to run a shell script:

(defun bk-konsoles ()
  "Calls: bk-konsoles.bash"
  (interactive)
  (shell-command (concat (expand-file-name "~/its/plts/goodies/bk-konsoles.bash ")
                         (if (buffer-file-name) 
                             (file-name-directory (buffer-file-name)))
                         " &") 
                  nil nil))

If I start a program with no ampersand - it start the script, but blocks emacs until I close the program, if I don't put ampersand it gives error:

/home/boris/its/plts/goodies/bk-konsoles.bash /home/boris/scl/geekgeek/: exited abnormally with code 1.

Edit:

So now I'm using:

(defun bk-konsoles ()
  "Calls: bk-konsoles.bash"
  (interactive)
  (shell-command (concat (expand-file-name "~/its/plts/goodies/bk-konsoles.bash ") 
                         (if (buffer-file-name) 
                             (file-name-directory (buffer-file-name))) 
                         " & disown") 
                 nil nil)
  (kill-buffer "*Shell Command Output*"))

Edit 2:

Nope - doesn't work:

(defun bk-konsoles ()
  "Calls: bk-konsoles.bash"
  (interactive)
  (let ((curDir default-directory))
    ;; (shell-command (concat "nohup " (expand-file-name "~/its/plts/goodies/bk-konsoles.bash ") curDir) nil nil)
    (shell-command (concat (expand-file-name "~/its/plts/goodies/bk-konsoles.bash ") 
                           curDir "& disown") nil nil)
    (kill-buffer "*Shell Command Output*")))

keeps emacs busy - either with disown, or nohup.

Here's a script I'm running if it might be of help: bk-konsoles.bash