OMG! Someone missed me!
I can help you with ajax if you still need help, its really not that hard.
Basically this is how it works:
AJAX basically is Javascript that runs asycnroniously(basically while other code is running) and retreives XML files from a server. PHP is a server engine that basically can retreive data from a MySQL server and then, using that data, generate XML or HTML or really any type of text file.
SO, all you need to do is this: Go to jquery.com, download jquery (DO THIS, IT WILL MAKE YOUR LIFE PROGRAMMING THIS GAME AT LEAST 500x EASIER (I MEAN IT))
Then read the documentation.
With Jquery you can actually run an entire AJAX command with one line of code.
Its awesome.
So yea,
Mist