You might want to inject an "Unofficial" in the title or somewhere to clarify that ICBIT did not author this.
Final settlement value is determined on listed the day of settlement for each instrument (currently 14th Apr, 14th Jun and 16th Sep) and is based on the spot price of BTC/USD on that day.
Because that could be misinterpreted, each contract type specifies the method that determines the settlement value . For BTC/USD contracts, the final settlement value is the 24 hour volume weighted average price (VWAP) from the largest exchange at the time of the settlement (i.e., 20:00 UTC).