Yule is the celebration of the winter solstice, usually around the 21st/22nd of December. Christmas is a Christian-based, and sometimes secular, holiday based on the birth of Christ on December 25.
Christmas takes many of it's traditions (wassail, trees, wreaths, gifts, colors, etc.) from the Yule celebration. Even the date relates to Yule. According to scholars, Christ would not have been born in the winter (when do sheep give birth? early fall?) and the early church MOVED the celebration to make it more "pagan-friendly" as an attempt to convert them.
Yule celebrates the birth of the Sun God. Christmas celebrates the birth of the Son of God.
So, basically.... Other than the date, there's not a WHOLE lot different.
at 2:49 PM on Nov. 2, 2010