The section:
echo "Upload: " . $_FILES["file"]["name"] . "<br />";
echo "Type: " . $_FILES["file"]["type"] . "<br />";
echo "Size: " . ($_FILES["file"]["size"] / 1024) . " Kb<br />";
echo "Temp file: " . $_FILES["file"]["tmp_name"] . "<br />";
gives the extra info to which I assume you are referring. Therefore, just change it to:
echo "Thanks for uploading";
Do your users log in, or is this an anonymous uploader? If they log in, you could retrieve the user name, and have it create a directory. For example, if your user name were stored in the string $username, you could change any occurence of:
"upload/" . $_FILES["file"]["name"]
to:
"upload/" . $username . "/" . $_FILES["file"]["name"]
Even if you don't have a user, you could have a form with an input box, and use the value from that form in the same manner. I assume you know how to do that, as you mentioned you can do the forms. You could do it with the same code I just gave you, and somewhere above that declare the string, e.g.:
$username = $_POST["whateverYourFormTitleIs"];