<a class="button" href="#"><span>Bring world peace</span></a>

.clear { /* generic container (i.e. div) for floating buttons */
overflow: hidden;
width: 100%;
}

a.button {
background: transparent url('bg_button_a.gif') no-repeat scroll top right;
color: #444;
display: block;
float: left;
font: normal 12px arial, sans-serif;
height: 24px;
margin-right: 6px;
padding-right: 18px; /* sliding doors padding */
text-decoration: none;
}

a.button span {
background: transparent url('bg_button_span.gif') no-repeat;
display: block;
line-height: 14px;
padding: 5px 0 5px 18px;
}

a.button:active {
background-position: bottom right;
color: #000;
outline: none; /* hide dotted outline in Firefox */
}

a.button:active span {
background-position: bottom left;
padding: 6px 0 4px 18px; /* push text down 1px */
}

<a class="button" href="#" onclick="this.blur();"> … </a>