On picking up a new O2 brochure just now the Sony Xperia S is listed with a PAYG price of £399.99 but at the moment is not in stock to buy. It does mean that March is the confirmed launch date though which is a good thing especially for the new Sony brand
No information on contract pricing yet, once we have that we will update everyone but at least we know now that a PAYG Xperia S will cost you £399.99 and will be in Black