Daniel Ribeiro has (re)published an article he originally wrote for the Web & PHP Magazine about becoming a PHP evangelist and helping to lead change in the community.
To evangelize is to effectively transfer information regarding one set of beliefs to another, with the final goal of converting each individual to the original belief. Isn't that what we do when we spread the word of PHP?! The idea behind being a PHP Evangelist is for an individual to speak passionately about PHP and be able to have strong and durable arguments for PHP, if questioned about his "faith" in the technology.
He talks some about the skills and things you'd need to become an evangelist - an advanced knowledge of the language, thinking "out of the box" about problems and how you can stand out from the other people in the community as a leader. He also recommends being technically adept as well and contributing to projects, either through support or actual development.
PHP evangelists are born to lead, to form opinions, influence the opinions of others and to have followers - and haters as well. Even if you think you were not born to be a leader or just don't want to be one, you will have to get used to public speaking if you wish to become a PHP evangelist.