vTemplate is a PHP class that is intended to make splitting PHP from HTML a simple and natural task. It has easily understandable syntax that is much easier to use than other template classes. It compiles a template into native PHP code using one PCRE call, thus the parsing is extremely fast. It also has powerful caching and debugging classes to extend the functionality.
ajax-cross-browser-using-iframes uses Iframes, an empty div, and innerHTML, allowing you to create AJAX calls. It is a little bit confusing at first, but once you understand it and place the necessary nested PHP files, it will allow you to create unimaginable things. It is cross-browser.