This is my first SE mobile and i am not quite familiar with the interface, I spent about 1 day to figure out how to use the wifi in the application.
"Currently Unavailable" - in the Internet Settings of the Application
Thanks to the friendly interface, it's not difficult to setup your wifi network, it's straight forward. So you shouldn't be having problem with joining your wifi network. However, once you connected to your wifi network, you should be able to use the wifi signal to browse the internet and get the internet data in your application (like the gmail, MSN, google map, etc.).
Browsing the internet is fine, but the second part seems not so easy. If the application you are using need to use data connection, it will prompt you to the internet settings (you can also set this in Menu -> Settings -> Connectivity tab -> Internet Settings), and it has two options, 1 Connect Using: and 2. Allow local conn.

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