I need update iPhone4 s for wifi

Are you asking about updating iTunes?

Or updating your iPhone's IOS?

You don't update itunes for the iphone. You update itunes for your computer.

I still don't know what your trying to do.

YOu can only update your iphone IOS over wifi if your on IOS 5.0 or higher.

If you not you will have to connect your phone to yoru computer open itunes and update that way.

If your not on IOS 5.0 or higher, then you can't update the IOS without a computer. Sorry.

You need a computer with iTunes on it. Like I said you can't update your phone.

Well if you know that, then you should know that you can't upgrade the phone.