So...my web meandering paid off today! Check out this fantastic & FREE Photo Booth Sign. It's totally customizable too! You can use your names & they have some great color choices. I used the couples' names for one of our weddings coming up this weekend. Wow. Huge thanks to the Wedding Chicks for their generosity in sharing this cool design.
What I would suggest doing is printing the sign on heavy cardstock, hole-punching where the dots are on the side, and hanging with ribbon from a tree at your reception. Paper Source makes awesome thin ribbon in beautiful colors, I would suggest looking there! My other idea is to cut around the cloud shape, rubber cement down to wooden signs, and drive them into the ground (venue-permitting, of course!)
Enjoy, I hope to see some of these at our upcoming weddings ;-)