Q:

Disabling default tooltip

Here's a tooltip script, http://www.alessioatzeni.com/blog/simple-tooltip-with-jquery-only-text/. It works great in all the browsers but the default tooltip isn't disabled in IE.
How can i update the following script to disable the default tooltip? 
<script type="text/javascript">
$(document).ready(function() {
   // Tooltip only Text
   $('.masterTooltip').hover(function(){
         // Hover over code
         var title = $(this).attr('title');
         $(this).data('tipText', title).removeAttr('title');
         $('<p class="tooltip"></p>').text(title).appendTo('body').fadeIn('slow');
    }, function() {
         // Hover out code
         $(this).attr('title', $(this).data('tipText'));
         $('.tooltip').remove();
    }).mousemove(function(e) {
          var mousex = e.pageX + 20; //Get X coordinates
          var mousey = e.pageY + 10; //Get Y coordinates
          $('.tooltip').css({ top: mousey, left: mousex })
    });
});
</script>

A:

I don't see any reason to add the title attribute back in to the element on blur.  You have it stored in the jQuery metadata.  My guess is that is why IE is still showing it.  Remove the line
        $(this).attr('title', $(this).data('tipText'));

and see if that fixes it.

EDIT:  That missed some requirements.  This is untested, but might work:
$(document).ready(function() {
    $('.masterTooltip').each(function() {
        var title = $(this).attr('title');
        $(this).data('tipText', title).removeAttr('title');
    }).hover(function(){
        $('<p class="tooltip"></p>')
        .text($(this).data('tipText'))
        .appendTo('body')
        .fadeIn('slow');
    }, function() {
        $('.tooltip').remove();
    }).mousemove(function(e) {
        var mousex = e.pageX + 20;
        var mousey = e.pageY + 10;
        $('.tooltip')
        .css({ top: mousey, left: mousex })
    });
}); 

Note that this is sub-optimal, as it calls $(this) twice in the each block, but that should be easy enough to fix.

