Same idea as the other replies... Don't know what flavor of unix you are on, but on Solaris, ps -fo 'pid= args=' will list processes (for a user) giving only their PID and the argument list (including the script name) this might make it easier to parse through the results and look for your own proc.
I have a perl subroutine that does exactly what you want, though it is a little complex cause it does all kinds of logging, etc if the procname and userID passed to it do not exist, etc. But bottom line is execute a ps, capture the results and count the lines containing it...
Also, as the last reply said, you can set a flag (touch a file) that signals the proc is active (each run must check to see if the file already exists). You can also use semaphors (if your unix supports sys V IPC calls) to do the same thing.... I can send you the perl routine if you want....
quine@sonic.net