how can i find my icloud ID

how can i find my icloud ID ? i had upgraded my iphone4 to IOS7 and created an Icould ID, after couple of months my phone was restored and when i am trying to use my iphone4 it is asking me for icloud ID please see the exact message in bracket (This iPhone is currently linked to an Apple ID (s●●●●●@icloud.com). Sign in with the Apple ID that was used to set up this iPhone.) please do needufl.