I searched on a lot of Apple sites to find an easy shutdown script. shutdown -h -t xx works fine in the Terminal, but it's too clumsy. So I managed to make a (very) little AppleScript (my first one, BTW) which works.
(* how many seconds before we remove the notice? *)
property dialog_timeout : 3
repeat
try
display dialog "In how many minutes must the computer be shutdown?" ¬
default answer ""
set the time_amount to the text returned of the result as integer
if the time_amount is greater than 0 then exit repeat
on error number error_number
if the error_number is -128 then return "user cancelled"
end try
end repeat
if the time_amount is 1 then
set the my_minuten to "minute"
else
set the my_minuten to "minutes"
end if
display dialog "The computer will be shutdown in " & time_amount & " " & ¬
my_minuten & "!" buttons {"Ok"} default button 1 giving up after dialog_timeout
delay time_amount * 60
tell application "Finder" to shut down
There is no canceling as I know, that would a nice addition...
Mac OS X Hints
http://hints.macworld.com/article.php?story=20040209142949995