So cute. I think the site has the skirts merchandised kind of frumpy, but you could easily create youthful and fun looks with these skirts. For the black skirt, I would match it with a crisp white shirt and lots of gold necklaces. The yellow skirt would be worn with a light t-shirt for a more casual look. Some cute sandals or wedges would lighten the whole outfit up and not look so hippyish.
You can find a whole bunch of long skirts at http://www.sundancecatalog.com/. If you have time, check out their jewelry. My sister swears they have the best, least expensive- but looks expensive stuff.