Google Maps 、日本では米国ほどプライバシー論争は起こらないだろうけれど、丸見えです。
人形アイコンをクリックすると InfoWindow が開き、さらに 
をクリックすれば最大化されます。
Google Maps API ストリートビュー（その１）（新しいウィンドウで開く）
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8"/>
<title>Streetview API</title>
<script type="text/javascript" src="http://www.google.com/maps?file=api&v=2&key=YOUR-KEY"></script>
<script type="text/javascript">
var marker;
var overlayInstance = null;
var map;
var client;
var lastMarkerLocation;
var panorama;
var mapT;
function load() {
client = new GStreetviewClient();
var latlng = new GLatLng(35.658725, 139.746222);
map = new GMap2(document.getElementById("map"));
map.setCenter(latlng, 15);
map.addControl(new GSmallMapControl());
var guyIcon = new GIcon(G_DEFAULT_ICON);
guyIcon.image = "http://maps.google.com/intl/en_us/mapfiles/cb/man_arrow-0.png";
guyIcon.transparent = "http://maps.google.com/intl/en_us/mapfiles/cb/man-pick.png";
guyIcon.imageMap = [
26,13, 30,14, 32,28, 27,28, 28,36, 18,35, 18,27, 16,26,
16,20, 16,14, 19,13, 22,8
];
guyIcon.iconSize = new GSize(49, 52);
guyIcon.iconAnchor = new GPoint(25, 35);
guyIcon.infoWindowAnchor = new GPoint(25, 5);
marker = new GMarker(latlng, {icon: guyIcon, draggable: true});
map.addOverlay(marker);
lastMarkerLocation = latlng;
GEvent.addListener(marker, "dragend", onDragEnd);
GEvent.addListener(marker, "click", openPanoramaBubble);
toggleOverlay();
}
function openPanoramaBubble() {
var contentNode = document.createElement('div');
contentNode.style.textAlign = 'center';
contentNode.style.width = '500px';
contentNode.style.height = '300px';
contentNode.innerHTML = 'Loading panorama';
marker.openInfoWindow("<div id='pano' style='width:240px;height:200px;'><\/div>", {maxContent: contentNode, maxTitle: "Full screen"});
panorama = new GStreetviewPanorama(document.getElementById("pano"));
panorama.setLocationAndPOV(marker.getLatLng(), null);
GEvent.addListener(panorama, "newpano", onNewLocation);
GEvent.addListener(panorama, "yawchanged", onYawChange);
var iw = map.getInfoWindow();
GEvent.addListener(iw, "maximizeend", function() {
panorama.setContainer(contentNode);
window.setTimeout("panorama.checkResize()", 5);
});
}
function toggleOverlay() {
if (!overlayInstance) {
overlayInstance = new GStreetviewOverlay();
map.addOverlay(overlayInstance);
} else {
map.removeOverlay(overlayInstance);
overlayInstance = null;
}
}
function onYawChange(newYaw) {
var GUY_NUM_ICONS = 16;
var GUY_ANGULAR_RES = 360/GUY_NUM_ICONS;
if (newYaw < 0) {
newYaw += 360;
}
guyImageNum = Math.round(newYaw/GUY_ANGULAR_RES) % GUY_NUM_ICONS;
guyImageUrl = "http://maps.google.com/intl/en_us/mapfiles/cb/man_arrow-" + guyImageNum + ".png";
marker.setImage(guyImageUrl);
}
function onNewLocation(lat, lng) {
var latlng = new GLatLng(lat, lng);
marker.setLatLng(latlng);
}
function onDragEnd() {
var latlng = marker.getLatLng();
if (panorama) {
client.getNearestPanorama(latlng, onResponse);
}
}
function onResponse(response) {
if (response.code != 200) {
marker.setLatLng(lastMarkerLocation);
} else {
var latlng = new GLatLng(response.Location.lat, response.Location.lng);
marker.setLatLng(latlng);
lastMarkerLocation = latlng;
openPanoramaBubble();
}
}
</script>
</head>
<body onload="load()" onunload="GUnload()">
<div id="map" style="width: 550px; height: 380px; border: 1px solid black;"></div>
<form action=""><p> <input type="button" onclick="toggleOverlay()" value="Toggle"/></p></form>
</body>
</html>
ついでにこんなのも API で作れます。・・・Street View はフラッシュだから、Maps API for Flash にこの機能が追加されたら、当然レスポンスもいいと思います。