Hide only visually, but have it available for screen readers: http://snook.ca/archives/html_and_css/hiding-content-for-accessibility
Taken from HTML5 Boilerplate CSS.
.visuallyhidden {
border: 0;
clip: rect(0 0 0 0);
height: 1px;
margin: -1px;
overflow: hidden;
padding: 0;
position: absolute;
width: 1px;
}