No windows update still works. Just no newer updates.
But if you want to use this program
http://download.wsusoffline.net/
On the right hand side it says Version 9.1 Click on that and download it. The extract the files in from the ZIP. Then run the Update Generator and just select the stuff for XP. If your install has SP3 intergraded with it then uncheck the Include Service Packs at the bottom to save time and space. Then you can click start.
What this will do is download all the updates after SP3 to your PC. Then once that is done if you go into the Client folder and run the Update Install it will install all the updates in one go (That is if you slect the Automatic Reboot and Recall)
Now i don't think its ALL the updates but...