I've seen these on various blogs. For the fabric one I printed out a flower pattern and added different sizes so I could have more on my pin. Then for the circle one I just used cups. I used a small circle of felt on the back and stitched on a pin back. Then I just attached the fabric to that through the button and back through the pin back.
The most time consuming thing out of them was making the patterns. I cut them out of paper and then out of a thin cardboard (from a 12 pack of soda). I have been able to reuse the cardboard patterns to cut out my fabric. I'm planning on making quite a few of these for gifts, so I'm going to cut a bunch of fabric out and then just sit down one night to stitch them all together.
Linking to Diary of a Craftaholic