humm maybe somthing like this?..
<?
function form() {
?>
<form name="test" method="post" action="<? echo $PHPSELF ?>">
<input type="text" name="user">
<input type="submit" name="Submit" value="Submit">
</form>
<?
}
if ($_POST['Submit'] == "Submit") {
//After user hits submit on form
echo $_POST['user'];
} else {
form();
}
?>