I made a poinsettia wedding cake and used both tutorials mentioned in Peridot's post. http://www.cakecentral.com/modules.php?name=gallery&file=displayimage&pid=1291905
I ordered the cutters and gumpaste from Global Sugar Art. I used the red and green mexican gumpaste by Marcela Sanchez and it was a dream to work with. You can roll it really, really thin and and it stays flexible longer than other gumpaste. The color was beautiful, I didn't have to add any color to it.
The instructions seem a little overwhelming at first but once you get your method down, they are pretty quick to make. PM me if you have any questions, I am no expert but I may be able to lend a hand!