Here are a few links to help you with drag and drop:
http://geekswithblogs.net/AzamSharp/archive/2008/02/21/119882.aspx
http://www.codeproject.com/KB/webforms/JQueryPersistantDragDrop.aspx
It's really easy but you have to write the code based on your specific application.
In the onDrop method, you need to write an Ajax request to POST the data you want to save. The JQuery AJAX API is here:
http://docs.jquery.com/Ajax/jQuery.post#urldatacallbacktype
The POST URL should refer to the PHP script which will save the data. On the PHP side, you connect to the DB:
<?php
$dbc = mysql_connect('localhost:/private/tmp/mysql.sock', 'root', 'password') or die (mysql_error());
mysql_select_db('database_name');
?>
Then you write an INSERT statement. This is an insert statement for music shows:
$sql_insert = "INSERT INTO shows (date,venue,venueLink,location,comment,time,dateOrder,locComment,confirm_by) VALUES ('".$Date."', '".$Venue."', '".$VenueLink."', '".$Location."', '".$Comment."', '".$Time."', '".$dateSort."', '".$locComment."', '".$confirmAll."')";
$Venue, for example, would be a variable in your AJAX post request. You can get these variables from PHP superglobals:
$Venue = $_POST['venue']
FYI: You can make that query look much better because double quotes actually print variables...I just copied and pasted some noob code I found from a while back. You can worry about making it pretty later.