Ajax Load

Generally this is done by showing/hiding a div or two over the top of your content. You can get a fancy loading gif fromhttp://www.ajaxload.info/ to get you started. Then you'll want to place a DIV on your page:

<div id="loading">

  <p><img src="loading.gif" /> Please Wait</p>

</div>

You'll want this hidden by default, so you'd need to add this CSS:

#loading { display:none; }

You'd also want to setup the display for this too:

#loading { display:none; position:fixed; left:0; top:0; width:100%; height:100%;
           background-image:url("transparentbg.png"); }

The file transparentbg.png would be a 25x25 black PNG set to about 80% opaque. Next you would need a way to show and hide this with jQuery:

function showLoading() {
  $("#loading").show();

}
function hideLoading() {

  $("#loading").hide();
}

Now you can use this when you need to do something like querying an external page for data:

showLoading();
$.post("data.php", {var:"foo"}, function(results){

  $("content").append(results);

  hideLoading();
});