There was a post on Adomas Paltanavicius website giving a tutorial about mouse wheel programming in JavaScript. It is a pretty clever idea and doing more and more AJAX-like applications I can see this tutorial becoming more and more useful. At this time I never really thought about implementing code for the mouse wheel but in upcoming projects I think I will find this tutorial very helpful.
I tested it in most browsers and for the most part it seems to work. He also gives two map examples Google Maps and ACME Mapper that utilize similar mouse wheel functions in their AJAX applications.









