This script sends automatically an SMS using ttytter:
-when someone is bruteforcing your PC, using auth log login failure notification
-when someone has connected to your server, using iptables log and a user predefined port in the script;
-the load past 15 minutes is higher than a set value.
You must have ttytter installed on your machine. For ttytter to work, perl 5.8.6, curl or lynx.

For how to install and configure ttytter check the following link:
http://www.floodgap.com/software/ttytter/

You have to add the script to crontab. I recommend running it every 5 minutes.

For using the CPU and HDD utility you must have sensors set up and hddtemp installed and a sticky bit permision for it.