my iphone has itunes symbol and usb symbol on screen and its locked

i plugged my iphone4s to my laptop and it did the updates but never synced my phone. now my phone has an "itunes" emblem with an arrow and "usb" emlem and its stuck! how do i get rid of it and use my phone again? this is the 2nd time its happened (over a month ago) and i forgot how i got rid of it.

PLEASE HELP!!