CSS3 pulsing dots, http://jsfiddle.net/24GXr/ and with fade in and fade out http://jsfiddle.net/qnN6B/

index.html

<div class="pulse green"></div>
<div class="pulse yellow"></div>
<div class="pulse red"></div>

styles.css

html {
    background-color: #232323;
}
.pulse {
    margin: 30px;
    width: 10px;
    height: 10px;
    background-color: #749a02;
    border-radius: 5px;
}
@-webkit-keyframes greenPulse {
    from {
        background-color: #749a02;
        -webkit-box-shadow: 0 0 9px #333;
    }
    50% {
        background-color: #91bd09;
        -webkit-box-shadow: 0 0 18px #91bd09;
    }
    to {
        background-color: #749a02;
        -webkit-box-shadow: 0 0 9px #333;
    }
}
div.pulse.green {
    -webkit-animation-name: greenPulse;
    -webkit-animation-duration: 2s;
    -webkit-animation-iteration-count: infinite;
}
@-webkit-keyframes yellowPulse {
    from {
        background-color: #fc9200;
        -webkit-box-shadow: 0 0 9px #333;
    }
    50% {
        background-color: #ffb515;
        -webkit-box-shadow: 0 0 18px #ffb515;
    }
    to {
        background-color: #fc9200;
        -webkit-box-shadow: 0 0 9px #333;
    }
}
div.pulse.yellow {
    -webkit-animation-name: yellowPulse;
    -webkit-animation-duration: 2s;
    -webkit-animation-iteration-count: infinite;
}
@-webkit-keyframes redPulse {
    from {
        background-color: #bc330d;
        -webkit-box-shadow: 0 0 9px #333;
    }
    50% {
        background-color: #e33100;
        -webkit-box-shadow: 0 0 18px #e33100;
    }
    to {
        background-color: #bc330d;
        -webkit-box-shadow: 0 0 9px #333;
    }
}
div.pulse.red {
    -webkit-animation-name: redPulse;
    -webkit-animation-duration: 2s;
    -webkit-animation-iteration-count: infinite;
}