How to remove header title

in style.css, add text-indent: -9999px; to the styles of the header title and description:

.header_title {
	font: bold 28px "Trebuchet MS";
	position: relative;
	left: 38px;
	top: 80px;
	width: 852px;
text-indent: -9999px;
}

and assuming that you want to move the description as well:

.header_desc {
	font-size: 18px;
	border-bottom: none;
	color: #000;
	position: relative;
	top: 80px;
	left: 38px;
	width: 852px;
text-indent: -9999px;
}