Birkat hanatan mikvodo
The blessing on seeing a king or queen
There are blessings in Judaism for seeing a king or queen. The one for seeing a non-Jewish monarch runs: "Blessed are you… who gives from his glory to flesh and blood" .The one for a Jewish king is worded slightly differently. It is not currently relevant, and probably won't be until the Messiah comes.
The blessing implies two important ideas. First, the glory and splendour surrounding the monarch are somehow a reflection of those qualities that attach to God. Second, that the human being who has acquired this glory, is after all, flesh and blood, a regular, fallible person just like us. The Shulchan Aruch adds that one should seek opportunities to see kings in order to say this blessing and glimpse this reflected glory. Today of course, now that we know just exactly the ways in which the royals are fallible flesh and blood, it is rather hard to appreciate this idea.
The question of whether you may say the blessing if you see the monarch on TV or the internet recently came up around the royal wedding. I think the answer is probably no - otherwise royal junkies plugged into 24-hour news stations would be saying it constantly.