css

divs justify

http://jsfiddle.net/thirtydot/EDp8R/
#container {
    border: 2px dashed #444;
    height: 125px;
    
    text-align: justify;

    /* just for demo */
    min-width: 612px;
}

.box1, .box2, .box3, .box4 {
    width: 150px;
    height: 125px;
    vertical-align: top;
    display: inline-block;
    *display: inline;
    zoom: 1
}
.stretch {
    width: 100%;
    display: inline-block;
    font-size: 0;
    line-height: 0
}