I'm with the folks who say it's bad form to cite any encyclopedia in a college-level paper. Better to find the original source. But encyclopedias are great for double-checking names, dates, etc. Most of what you find in an encyclopedia will fall under the category of "common knowledge" and need not be cited anyway (stuff like the dates of the 100-years-war, the chemical formula for benzene, etc. are common knowledge and you don't have to cite them).
Wikipedia works most of the time for this, but it's better if you can independently verify what you find in Wikipedia.
FWIW, I'm the author of "Researching Online," a college level research guide.