Just kill the ssh process. What do you mean by "sleep option"?
Or maybe you want to open an ssh session to forward the vnc port and then you want the terminal window to go away?
Oh! I just looked at the openssh faq and I see what you mean by "sleep option".
(
OpenSSH FAQ for the curious bystander...) So, yes, you do want to forward a port without leaving a terminal running...
This isn't a really good answer, but it's what I do:
ssh -q -o BatchMode=yes -i $KEY -N -L $SOURCE.$PORT1:$DEST:$PORT2 $ACCNT@$OTHER_HOST &
SSHPID=$?
# start vncviewer
kill $SSHPID
That's from memory and untested, so consider it pseudo code.