Variable variables are often the wrong answer, but every now and then, they are the right one.
Having not really gotten enough from you to be sure what exactly you're doing, I'm not sure here, but I'm guessing you don't really need them here.
Generally, the best way to build drop downs is to do something like this:
$info = array("red","green","blue");
print "<SELECT name=\"color\">
foreach($info as $k=>$v){
print "<option value=\"$k\"";
if ($color==$k) print " SELECTED";
print ">$v</option";
}
print "</SELECT>";
Whatever the user selects, you will get the numeric key back that was defined. As you can see, you could just as easily replace that number with a row id or something from a database. If the value is selected and the form submitted, the if ($color==$k) part will make sure it is selected in the form. Add a "onchange=document.formname.submit() to the select input element makes it autosubmit.