Learn to Dance DVD

I am looking to get an Instructional DVD on ballroom dancing. I don't know exactly what ballroom dancing is, so I don't really know what to look for. I have never danced before, I plan on buying it and learning with my girlfriend for her birthday. She knows how to swing dance and she said she would like to learn ballroom dancing.

Does anyone have any info or specific DVDs for a beginner ballroom dancer?

Thank you!

You can learn some basic patterns at sites like http://www.ballroomdancers.com and you can get pretty well all the DVD's you'd like at http://www.dancevision.com , among others.
That said, I'd strongly urge you NOT to delude yourself into thinking you can learn to dance from videos, or even save money from them. You can see some figures and get a rudimentary understanding of what music matches what dance, but the connection and communication that make up 90% of ballroom dancing have to be learned by feel. You can learn some basics in group lessons, but you really won't begin to learn how to dance until you each have occasional private lessons as well. For instance, I still have a bad habit in standard dances of letting my right elbow drop an inch or so. A pro can feel that and may even see it, but we mere mortals would never notice.