Blue and White
You've seen those buildings in the Greek islands, right? The white buildings with the blue roofs? Try that look for your summer wedding. Nothing says summer like the beach, and the color of the Mediterranean is perfect for a summertime wedding. Using a tropical shade of blue will give your wedding a calm, relaxed feeling, and pairing it with a crisp white can capture that cool, beachy feel. Let's also mention that Pantone, the company that writes the book on color, has named turquoise as the 2010 color of the year, so you should be able to find great ways to use blue everywhere. It doesn't hurt that most people look good in blue, so your bridal party will be happy to wear almost any shade of this color.
White can keep the blue from going overboard. Use white flowers, and add blue ribbons for bridal bouquets, boutonnieres and flowers along the aisle. Look for blue vases to use as centerpieces on stark white tablecloths. Having your wedding outside? Create cozy, romantic cabanas with couches adorned with blue and white pillows, all covered with gauzy white fabric. String up white lights everywhere for a twilit touch.