From Adobe: Beginning today, "customers who purchase Creative Suite 5.5 (CS5.5) software will receive a complimentary upgrade to CS6 when it becomes available. No coupon code necessary, offer valid in North America and the European country stores listed below."
North America Store: Buy CS5.5 now and get CS6 at no additional cost. Offer ends May 6, 2012.
European Store: Buy CS5.5 now and get CS6 at no additional cost. Offer ends 6 May, 2012.
(Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Ireland, Italy, Luxembourg, Netherlands, North America, Norway, Poland, Portugal, South Africa, Spain, Sweden, Switzerland, Turkey, and The UK.)