Ajax might not just be the darling of the web, think of the applications it could be used for on your mobile. Opera is spearheading this drive and they have a great resource on the possible application for Ajax enabled apps built for mobile phones. The first things that come to mind are CRM applications and then what about integrating with gps enabled devices. The oportunities are endless and all you have to know is how to code a web based app, easy hey!