i need a little help i want a script which will check the version of the script from the main server and tell whether its latest or not.
Should be fairly easy to implement. Do you have the script website? If they provide any sort of feed from their website about that particular script you could just get the latest update and verify it with your script. Otherwise, you may just consider parsing the HTML for the download page, getting the lates version from there and verifying it that way.
the only thing u need to consider is that the main server should not get overloaded because of repeated checks. so u should set some kind of timings on which it checks and not everytime the site is loaded.
Via XML? You mean like a feed and parse the latest version out? http://www.php.net/manual/en/ref.xml.php