The dimensions of an Olympic standard pool is 50 metres long, 25 metres wide, and at least 20 metres deep at the deepest end. That's 25,000 cubic metres or about 482,500 tonnes of gold.
According to the current value of gold (Nov 3,2009) that would be worth 11,372,258,723,667 Euros. (Over 11 Trillion Euros)
(Incidentally, that would be over three times the total amount of gold mined since the beginning of human history)
If you were to estimate those numbers, It would be nearly 650,000 of gold.