.tickercontainer { /* the outer div with the black border */
width: 490px; 
height: 50px; 
margin: 0;
padding: 0;
overflow: hidden;
float: left;
}
.tickercontainer .mask { /* that serves as a mask. so you get a sort of padding both left and right */
position: relative;
/* left: 10px; */
top: 20px; 
width: 100%;
overflow: hidden;
}
#container ul.newsticker { /* that's your list */
position: relative;
left: 100%;
list-style-type: none;
margin: 0;
padding: 0;

}
#container ul.newsticker li {
float: left; /* important: display inline gives incorrect results when you check for elem's width */
margin: 0;
padding: 0;
}
#container ul.newsticker a {
white-space: nowrap;
padding: 0;
margin: 0 20px 0 0;
} 
#container ul.newsticker span {
margin: 0 10px 0 0;
color: #fff;
}