Yule is the first day of the winter solstice, and is also the shortest day of the year. It's a time when the Holly King's reign ends, and the Oak King takes over. It's a time to honor the Goddess of Darkness and the Horned God, and the rebirth of the Sun God. It represents rebirth, and the turning of the Earth's force tides.
Most Pagan's believe in reincarnation. At this time of the year, we celebrate it! This cycle of life and death for the God, is symbolic of the belief in life from death.
If you happen to wander into a witch's house during this time of year, you are liable to notice that she has decorated! It is custom for a witch to decorate her dwelling with Yule Logs (oak or pine), Mistletoe, wreaths, strings of dried flowers and cinnamon sticks, and Yule trees. She will also most definatly have her tables adorned with apples, nuts, oranges, caraway rolls, Mulled wine and roast turkey.
In short, Yule is truely a festive time, where one must reflect upon the past years acheivements, and to celebrate with family and friends!