My iphone 4s is not being recognised by my itunes I have just got the new iphone 4s and when I am trying to sync it with my itunes it is not being recognised.
I have downloaded the new itunes twice so I am sure it is up to date. 
Does anyone have any other solutions I can try?
You will need to reinstall the Apple Device manager,

If you are using windows here is the page on apple support that outlines the process below. If you are using OSX see this page here

make sure you uninstall all the itunes apps, including device manager, once thats done, download an install iTunes again.

That should all now work.