The letter É is pronounced ▶ Play. It is not a single sound but two, “é” is pronounced like “je” – exactly the same as the English word “yeah” – you start with an Icelandic J sound and end with an E sound.
It can be long:
  • tré, séð
Or short:
  • rétt, flugvél
The name of the letter is just “é” ([je]).