Found this tutorial on Ajax through del.icio.us, the tagged bookmarks website
http://dhtmlnirvana.com/ajax/ajax_tutorial/#
(my del.icio.us page is here)
The tutorials starts from the basics and builds it up - have'nt gone through it completely but seems to be one of the best tutorials on the subject yet
Ajax is an acronym given to a collection of existing technologiesan which are intended to improved the user's web surfing experience by reducing the time taken between a click-button -> page submit -> page refresh with new data - Ajax reloads the data in a table or an image in a div etc. without an annoying page refresh
Ggl uses Ajax extensively including in maps, personalized home and gmail
Some other very good examples of Ajax usage are protoPage and start.com, supposedly the MSN portal for people with a normal aesthetic sense
