This is an easy project to do and there are lots of variations on the internet. What I like about these charms is using metal binder rings to attach to the glasses. The ring binders are super easy to attach and remove from the glass stems.
supplies used: leftover wine corks (the cork kind, not plastic), metal binder rings (from ART-C), metal screw eyes (from Tim Holtz Idea-ology), VersaMark Black Ink pad, various rubber stamps, acrylic paint and brushes, Weldbond Glue, Modge Podge, craft knife, and something to hold the cork to keep your fingers safe (small clamp, large binder clip, pliers, etc)
I used a pliers to hold the corks and cut them into disks using a large craft knife. I didn't measure them - just eyeballed the size of the slices. Now I've read (but didn't try this) if the corks crumble when cutting then try steaming them. Place the corks in a bowl over a pot of boiling water and steam for a few min until they get soft and pliable. Allow to cool before cutting. If I decide to do another wine cork project that requires larger cut I may try this.
Next I took the screw eyes, dipped them into glue, and hand threaded them into the cork. I let them dry for about an hour. Next I painted one cut side with acrylic paint and let dry for about an hour before stamping. I found inking up the rubber stamp, laying it down, then pressing the cork pieces into the stamp worked best. I let the inked pieces dry overnight before sealing them with Modge Podge. Then I attached the rings and voila...some charming bling for my wine glass.