I feel like ever since we wedding guests found out we aren’t supposed to throw rice at the bride and groom (birds eat it, it swells in their bird-sized bellies), we’ve been at loose-ends. Birdseed is out because you’re introducing non-native seeds into an area (and you don’t want the bride looking like Tippi Hedren in http://www.imdb.com/title/tt0056869/>“The Birds”).
Butterflies have their own obvious mortality problems, and confetti gets stuck everywhere.
So, how about a balloon release? http://www.balloonstomorrow.com> Balloons tomorrow has 100% biodegradable latex balloons. You can even have them customized with the wedding date, or a photo of you and your fiancé. Great for decorations, or to send you on your way.