In my site I allow users to make posts similar to twitters update list these posts are inserted via ajax/php into a mysql database when a user makes them and retrieved in the same way.

However the user has to refresh the page several times sometimes to see these new updates. I now want to set it up to work in a similar manner to twitter and facebook i.e. a user makes a new post and that post appears live on the 'wall' of updates right at the top.

Is there any way to do something similar using ajax or javascript? A tutorial that explains this perhaps?

Any help would be greatly appreciated.