Since you're not specific about what kind of information you want to know about Morgan le Fay and Queen Guinevere, I can give you only general--but, I hope, interesting--details about them.
Morgan le Fay: She's also known as Morgane, Morgana, and Morgaine. She is the older half-sister of King Arthur. Morgan practices magic; the addition of "le Fay" literally means "of the fairies," but it probably signifies that she is a sorceress. Depending on the version of the Arthurian legend you're reading, she is either a benevolent ally to Arthur or a wicked and merciless enemy. In some modern versions of the story, such as The Mists of Avalon, it is she who seduces Arthur and conceives Mordred. In the traditional tales, however, it is the other sister, Morgause, who is the seductress. In some stories, Morgan is the mother of Sir Gawain and Sir Gareth; in other stories, Morgause is their mother.
Queen Guenevere (or Guinevere): The daughter of King Leodegrance of Carmelide, she is betrothed to Arthur but falls instantly in love with Sir Lancelot when he comes to escort her to Camelot. Most of the tales include her adultery with Lancelot, which leads to the downfall of Camelot. In many of the tales, she and Lancelot of victims of fate; what might have happened if someone else had been sent to bring her to Camelot? She and Arthur have no children, and depending on the tale, she either becomes a nun or is executed for treason. In any case, she is a sad, tragic character.
I hope that is the kind of information you wanted. Be more specific, and we'll give you more.