One of the more detailed descriptions how to work with the AppCache Manifest in HTML5 is published here. But since you have no time to read all that:
If they do that, you have a fully fledged web app going, that is moved to the home screen on the iPhone easily and gives you a way to navigate around the app store for these simple applications.
There are some examples out in the wild, but I am amazed how little that feature of HTML5 is praised around the web.
Here is the condensed info:
- add the .appcache file type to your Apache config, so the server is delivering the right file type
- create the manifest (the simpler your pages, the simpler the file) like here
- add the rel link in your HTML header like shown in above link
that makes these web apps really powerful!