Markers As Links

Clicking on markers to go to web pages
<!DOCTYPE html>
<html>
<head>
<meta charset=utf-8 />
<title>Markers As Links</title>
  <meta name='viewport' content='width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no' />
  <script src='//api.tiles.mapbox.com/mapbox.js/v1.4.0/mapbox.js'></script>
  <link href='//api.tiles.mapbox.com/mapbox.js/v1.4.0/mapbox.css' rel='stylesheet' />
  <!--[if lte IE 8]>
    <link href='//api.tiles.mapbox.com/mapbox.js/v1.4.0/mapbox.ie.css' rel='stylesheet'>
  <![endif]-->
  <style>
    body { margin:0; padding:0; }
    #map { position:absolute; top:0; bottom:0; width:100%; }
  </style>
</head>
<body>
<div id='map'></div>
<script>
var map = L.mapbox.map('map', 'examples.map-20v6611k').setView([39.12367, -76.81229], 9);

// The GeoJSON representing the two point features
var geoJson = {
    type: 'FeatureCollection',
    features: [{
        type: 'Feature',
        properties: {
            title: 'Washington, D.C.',
            'marker-color': '#f00',
            'marker-size': 'large',
            url: 'http://en.wikipedia.org/wiki/Washington,_D.C.'
        },
        geometry: {
            type: 'Point',
            coordinates: [-77.03201, 38.90065]
        }
    },
    {
        type: 'Feature',
        properties: {
            title: 'Baltimore, MD',
            'marker-color': '#f00',
            'marker-size': 'large',
            url: 'http://en.wikipedia.org/wiki/Baltimore'
        },
        geometry: {
            type: 'Point',
            coordinates: [-76.60767, 39.28755]
        }
    }]
};

// Pass features and a custom factory function to the map
map.markerLayer.setGeoJSON(geoJson);
map.markerLayer.on('click', function(e) {
    e.layer.unbindPopup();
    window.open(e.layer.feature.properties.url);
});
</script>
The code and documentation to mapbox.js is hosted on GitHub where you can contribute changes and improvements.