HTML_AJAX is a PEAR package for performing AJAX operations from PHP.
If your interested in learning more, the HTML_AJAX Manual is a good place to start
There are many ways to get involved with the development of HTML_AJAX. The easiest way is to help improve the documentation here on this wiki. Reporting bugs on the PEAR site or on the mailing list is also useful. If you're a developer we're also looking for new people to help out with features and write examples.
We're also always looking for people to help test new releases. If you run a non-mainstream browser this is especially helpful.
If you want to help out with testing or development please join the mailing list. If you're just using HTML_AJAX feel free to join the mailing list as well. It's a great place to ask questions and give feedback.