I wrote a script that starts the connection and my iptables script. I just type <script name> on the command line and the iptables script starts that the dial-up connections.
Here is my problem, I want to write a script that will kill the connection. Right now I do a ps -x, find the PID and do a kill PID number, on the command line.
How do I do this? I can do a ps -x | grep ppp0 > /tmp/modpid and print the pid number and name and such to a file. I just done know the commands to extract the PID number from the file and issue a kill to it. Any help is greatly appericiated. Thanks

Does your system support pkill? Or you could do something similar to the following for the long way around:
ps -ef | grep procname | awk '{print $2}' | xargs kill

Look in the (/etc/) init.d or rc.d directory for the stop scripts your machine runs to shut itself down; You can hopefully read through some of these and use the same methods your distribution does as an example of how you should do it.

Thanks stickman, the ps -ef | grep/ ..... thing worked.