AjaxDaddy give you some real good free code sniplets on various different Ajax implementations. Although I don’t have use for this as I prefer from-scratch Ajax coding, this can be very useful for anyone who’s not familiar with Ajax technology.
For Your Reference, what is AJAX?
Ajax Hacks – This book has lots of little tips and tricks for your Ajax code, definitely recommended if you are serious about Ajax development/learning.
AjaxBuddy, a free repository of Web 2.0-style site tools, is great for site owners who don’t have time to learn an entire programming language, or just need a starter block of code to get building. Grab free, easy-to-modify code for Flickr-like editing fields, quick-loading slideshows and tabbed galleries, instant graphs, date-choosing calendars, and dozens more examples.