Flickr search for geotagged + some other tag:

javascript:(function(){
  t = prompt('Enter tag (e.g. eiffeltower)');
  window.location = 'http://flickr.com/photos/search/tags:geotagged,' + t + '/tagmode:all/';
})()

Flickr photo detail page to google maps:

javascript:(function() { 
  m = /\/([0-9]+)\//.exec(page_current_url); 
  a = global_photos[m[1]].tags_rawA; 
  for (i = 0; i < a.length; i++) {
    m = /^geo:lat=(-?[\.0-9]+)$/.exec(a[i]);
    if (m) lat = m[1];
    m = /^geo:lon=(-?[\.0-9]+)$/.exec(a[i]);
    if (m) lon = m[1];
  }
  location.href = 'http://maps.google.com/maps?ll=' + lat + ',' + lon + '&t=h';
})()

Google maps page to alert of geotags:

javascript:(function(){
  m = /ll=(-?[\.0-9]+),(-?[\.0-9]+)/.exec(location.href);
  prompt('geotags are:', 'geotagged geo:lat=' + m[1] + ' geo:lon=' + m[2]);
})()

Map to geotags:

javascript:(function(){
  ll = document.getElementById('link').href.match(/\Wll=([0-9\.\,\-]+)\W/)[1].split(/,/);
  str = 'geotagged geo:lat='+ll[0]+' geo:lon='+ll[1];
  prompt('geotags are:', str);
})()