All this buzz about Web 2.0, ajax, webapps and so on, it’s the second coming of the web hype machine, and maybe a bit more. But if you’re interested in reviewing all the library options available to you, check out the Open Source Applications Foundation’s wiki page for Ajax Libraries. It’s not comprehensive but it covers the big ones and there are some useful comments about each of the libraries to help you judge which might be most appropriate for the project you’re working on. For what it’s worth I’ve played around with a couple of these now just to see what’s entailed in implementing this stuff and the biggest issue is not so much finding a library to work with, it’s finding one with enough documentation and examples that you can figure out how to handle implementation without tearing your hair out in frustration. The community seems to be well aware of the issue though so hopefully we’ll see better documentation emerge shortly. Meanwhile you can get a head start on most folks by starting to experiment now.