Jason A. Clark has a nice article published in the Linux Insider about How to Build an Ajax Application from Scratch. Ajax is quite the boon... I really do need to get my hands dirty and try some things with it.
Many in the literature bandy Ajax about as the next big thing for Web applications. Depending on whom you are reading, you might hear how Ajax will revolutionize what people can expect from Web sites or how it's the latest Web trend bound to fizzle. The truth is somewhere in between. Chances are good that you have seen Ajax before, you just didn't know it.
There's also an article on Infotoday regarding AJAX in the library context in particular. He discusses bennefits for libraries, and including examples of it's implementation in several cases including enhancing federated and OPAC searches.
Libraries and information agencies have been slower to embrace Ajax, but it’s not for a lack of library-use cases. In a library setting, Ajax could be used for speeding up digital library search applications using a link to activate a process that matches multiple ISSNs to compile a list of electronic journals, or even making quick requests to validate a user’s personal information as they log into a “My accounts” section of the catalog.
See my short collection of Ajax links, particularly: