Sonny,
The Jabber for Iphone is available as product. You should be able to download from App store.
There is currently no API suport on iPhone/iPad or any of the mobile OS, the Jabber Web SDK currently support Windows and Mac on most browser.
You should be able to find more details on
jabberdeveloper.com. From the website, you will find very good information that covers requesting a test account and downloading the sample code, FAQ, etc to help you learn more about Jabber SDK.
Hope this help
Howard