I've been bike commuting in skirts and dresses once or twice a week this summer-- trips less than 5 miles, so no bothering with shorts with chamois, just compression-style shorts for the sake of modesty. I look for fairly full skirts in knit materials, knee length or a little shorter. There's a lot out there that will work just fine! I also am mindful of the cut on tops-- even on my trek 7.3fx, there have been a couple times when it felt like everyone could look straight down my top and see everything when I reached for the handlebars.

Including bikes in the wedding, how cool!