I need to convert a web app into ipad app. Stressing on style and events.
It really depends on the framework and techniques you used for the original web-app. There are plenty of frameworks out there to build an iOS-web-app. For example jQuery mobile, you also might want to have a look into phonegap.
For the first few steps I can really recommendend reading this free aviable book from o'reilly about creating iPhone-Apps with HTML, CSS and javascript.