aggressive,
<select id="graf" name ="igraf-list">
<option value="http://fx1.it-finance.com/FXStreetFlashPublic/itcharts.phtml?id2=&news=1&facebook=0&twitter=0&spot=GBPUSD&broker=lmaxforex&timezoneoffset=3&locale=ru_RU">USD/CAD</option>
<option value="http://fx1.it-finance.com/FXStreetFlashPublic/itcharts.phtml?id2=&news=1&facebook=0&twitter=0&spot=EURJPY&broker=lmaxforex&timezoneoffset=3&locale=ru_RU">EUR/JPY</option>
<option value="http://fx1.it-finance.com/FXStreetFlashPublic/itcharts.phtml?id2=&news=1&facebook=0&twitter=0&spot=EURUSD&broker=lmaxforex&timezoneoffset=1&locale=ru_RU" selected="selected" >EUR/USD</option>
<option value="http://fx1.it-finance.com/FXStreetFlashPublic/itcharts.phtml?id2=&news=1&facebook=0&twitter=0&spot=GBPUSD&broker=lmaxforex&timezoneoffset=3&locale=ru_RU">GBP/USD</option>
<option value="http://fx1.it-finance.com/FXStreetFlashPublic/itcharts.phtml?id2=&news=1&facebook=0&twitter=0&spot=NZDUSD&broker=lmaxforex&timezoneoffset=3&locale=ru_RU">NZD/USD</option>
<option value="http://fx1.it-finance.com/FXStreetFlashPublic/itcharts.phtml?id2=&news=1&facebook=0&twitter=0&spot=USDCAD&broker=lmaxforex&timezoneoffset=3&locale=ru_RU">USD/CAD</option>
<option value="http://fx1.it-finance.com/FXStreetFlashPublic/itcharts.phtml?id2=&news=1&facebook=0&twitter=0&spot=USDCHF&broker=lmaxforex&timezoneoffset=3&locale=ru_RU">USD/CHF</option>
<option value="http://fx1.it-finance.com/FXStreetFlashPublic/itcharts.phtml?id2=&news=1&facebook=0&twitter=0&spot=USDJPY&broker=lmaxforex&timezoneoffset=3&locale=ru_RU">USD/JPY</option>
</select>
<iframe id = "igraf" src="http://fx1.it-finance.com/FXStreetFlashPublic/itcharts.phtml?id2=&news=1&facebook=0&twitter=0&spot=EURUSD&broker=fxcm&timezoneoffset=istanbul:180&locale=ru_RU" width="400px" height="400px" frameborder="0"></iframe>
<script>
var select = document.getElementById('graf');
var frame = document.getElementById('igraf');
select.addEventListener('change', handler.bind(null, select));
function handler(el) {
var str='USD/CAD',
options = el.options,
index = el.selectedIndex;
if (options[index].innerHTML == str) frame.contentWindow.location.href='http://fx1.it-finance.com/FXStreetFlashPublic/itcharts.phtml?id2=&news=1&facebook=0&twitter=0&spot=EURUSD&broker=fxcm&timezoneoffset=istanbul:180&locale=ru_RU'
}
</script>
Здесь для одного фрейма, для второго сделай сам...