In order to build anything in a Web 2.0 kind of way, you are going to need to brush up your knowledge of Ajax. I have put together a list of frameworks to help you undestand whats available. no more reinventing the wheel, just build on top of a working framwork.

1: Prototype is a JavaScript framework that aims to ease development of dynamic web.

2: Script.aculo.us provides you with easy-to-use, compatible and, ultimately, totally cool JavaScript libraries .

3: TinyAjax is a small php5 library that allows you to easily add AJAX-functionality to existing pages and create new AJAX-enabled pages with just a few lines of code.

4: ZK is an open-source Web framework that enables rich UI for Web applications with no JavaScript and little programming. With event-driven feature-rich components, developing becomes as simple as programming desktops. With a markup language, desigining becomes as simple as authoring HTML.

5: My-Bic is easy Ajax for PHP5