All of the code in this month's column was written using a combination of JavaScript and XHTML. If you are unfamiliar with JavaScript, you might want to look at David Flanagan's JavaScript: The Definitiv e Guide, published by O'Reilly. The XHTML is surprisingly readable an d includes many comments and examples of use to developers. You can read it at www.w3.org/TR/xhtml1.

For more information about Google Maps, refer to the Google Maps API site at www.google.com/apis/maps. You also will need to go to that site to get a key, if you decide to sign up for the service.

A short book on the subject, called Pragmatic Google Maps, was written by Scott Davis and published by the Pragmatic Programmers (pragmaticprogrammers.com). It contains a lot of good advice for working with Google Maps and puts much of the API documentation into perspective.

The home page for Amazon Web Services (AWS) is www.amazon.com/gp/browse.html?node=3435361. From that page, you can register for an ID, download and read documentation (including code examples in a variety of languages), and participate in forums for AWS developers. A frequently updated Weblog with news and ideas about AWS is at aws.typepad.com.

All of Amazon's Web services can be accessed using either SOAP or REST. An overall introduction to SOAP, including XML examples, is at www.intertwingly.net/stories/2002/03/16/aGentleIntroductionToSoap.html.

The two geocoders mentioned in this column are geocoder.us (geocoder.us) and Brainoff's geocoder (brainoff.com/geocoder), both of which are mentioned in Pragmatic Google Maps.