What OS are you working in? If it is Linux, I would suggest that you follow andreychek suggestion and look into process accounting, as that would be a cleaner approach than writing your own script.

Nevertheless, the way I see a script like this working would look like this in psuedocode

get args from command line
do some checking for validity of the arguments
  (ie, is it a valid process number, does the user own the process, ar
+e the flags/signals valid)
open log file
  write info about user, processid, process name, whatever
close log file
system("kill",$args,$processid)
[download]

Scott