In the past I would just use my iPhone's email-to-txt email address. However, when I received the txt message, it wasn't formated very pretty, and it would have a different "From Number." So if we had a crazy day, I would have 20-30 message threads in my iPhone all about Nagios. [...] What I like out this setup is with Twilio, I can buy a phone number for $1 a month. So all my notifications come through the same number.

He's included the PHP code he uses to send the notifications (using the Twillo library) and the Nagios commands he configured to send the notifications to that script via the command line.

RBLs are a great way to get rid of a lot of SPAM (if you choose the right ones). On the other hand you (and users of your mail server) get in big trouble if your SMTP server gets listed on a common RBL.

Checking this manually is a job that sucks a lot, checking this automatically is an easy job with Nagios, PHP, Net_DNSBL and Console_Getopt.

He includes the parts you'll need - grabbing the PEAR package, the PHP script to make the request and the changes you'll need to make to the configuration files to make it all work together.