A few weeks ago Kate Middleton made headlines for wearing black to a wedding. Indeed, it used to be a fashion faux pas to wear black at a wedding. But times change and so does fashion etiquette. Today, it's perfectly acceptable to wear black to a wedding. The little black dress (LBD) can be a woman's most versatile fashion staple. The LBD is simple and classy, making it great for a wedding. You can always add a splash of color with a purse, necklace, or shoes.
Now, the main fashion rule for guests at a wedding is: Don't Upstage the Bride! That typically means that you shouldn't wear white or ivory. No one should end up confusing you with the bride! I personally also recommend avoiding flashy red dresses, but that's a matter of choice. Also, be sure to dress tastefully. Don't wear anything too low cut or see-through. Keep the attention where it belongs -- on the bride!