I've figured a way to produce a jump menu with target = blank.
Shove this in your <head>
Code:
<script type="text/javascript">
function MM_jumpMenuNewWindow (selObj, restore) {
window.open(selObj.options[selObj.selectedIndex].value);
if (restore) selObj.selectedIndex=0;
}
</script>
Then the form
Code:
<form action="" id="sites">
<select name="jumpMenu" id="jumpMenu" onchange="MM_jumpMenuNewWindow(this,0)">
<option value="#">Select a Site</option>
<option value="http://www.website1.com">website1</option>
<option value="http://www.website2.com">website2</option>
<option value="http://www.website3.com">website3</option>
</select>
</form>
I've tested it and it works.