If you have a form ...
<form action="select_test.php" name="frm">
<select name="cat" size="1">
<option value="1" SELECTED>Text 1</option>
<option value="2">Text 2</option>
<option value="3">Text 3</option>
</select>
<input type="submit">
</form>
... and a separate php file (called select_test.php) with ...
<?php
echo $_GET["cat"];
?>
... then either a '1', '2', or '3' is displayed.
It is the value attribute from the option tag (1, 2 or 3) that is sent, NOT the text between the option tags ("Text 1", "Text 2" or "Text 3").