[jQuery] Simple Tooltip

[shapper]

Hello,

I need a simple tooltip which html markup is only a div. I have the
following:

this.tooltip = function(){
        /* CONFIG */
                xOffset = 10;
                yOffset = 20;
                // these 2 variable determine popup's distance from the cursor
                // you might want to adjust to get the right result
        /* END CONFIG */
        $("a.tooltip").hover(function(e){
                this.t = this.title;
                this.title = "";
                $("body").append("<div id='tooltip'><span>"+ this.t +"</span></
div>");
                $("#tooltip")
                        .css("top",(e.pageY - xOffset) + "px")
                        .css("left",(e.pageX + yOffset) + "px")
                        .fadeIn("fast");
    },
        function(){
                this.title = this.t;
                $("#tooltip").remove();
    });
        $("a.tooltip").mousemove(function(e){
                $("#tooltip")
                        .css("top",(e.pageY - xOffset) + "px")
                        .css("left",(e.pageX + yOffset) + "px");
        });
};

How can I change this plugin to use CSS Class selectors?
And how can I add a parameter to define the tooltip div CSS Class?

Does anyone knows a better Simple Tooltip?

Most tooltips I see have complex markup and some of them even include
headers tags in the tooltip which in my opinion shouldn't happen.

Thanks,
Miguel