Simple XMLHTTP tutorial

http://www.oracle.com/technology/pub/articles/cioroianu-ajax-data.html?rssid=rss_otn_news
http://ajaxian.com/archives/devarticlescom-a-three-part-tutorial-sending-email-with-ajax
http://www.xml.com/lpt/a/2005/02/09/xml-http-request.html
http://www.onlamp.com/lpt/a/5841
http://www.webpasties.com/xmlHttpRequest/
http://www-128.ibm.com/developerworks/java/library/j-ajax1/index.html?ca=drs-

And simple example:
http://www.josesandoval.com/2005/03/xmlhttprequest-with-java.html
http://struts.apache.org/flow/templates-example.html
http://www.omnytex.com/articles/xhrstruts/
http://today.java.net/lpt/a/219
http://tudu.sourceforge.net/
RSS reader - http://www.xml.com/lpt/a/1672

And samples collections: http://www.fiftyfoureleven.com/resources/programming/xmlhttprequest/examples

Error handling of javascript
http://www.xml.com/lpt/a/2005/05/11/ajax-error.html

caching problem... 
http://jroller.com/page/coreteam?entry=ajax_caching_problem