I know you can order them online, but I'd love to know how to make my own to help raise awareness here. I also don't know if they are held as sacred and I wouldn't want to try making one if that might be considered wrong!
from SFT site -> http://www.indiemerchstore.com/sft/item/2101/ :
The Rangzen Bracelet was first designed by Tibetan political prisoners near Lhasa. These bracelets were originally woven from white and black yak hair, or whatever bits of thread were available in the prisons. It is patterned after the traditional slingshot used by Tibetan nomads. Today these bracelets are worn as an expression of endurance and defiance against Chinese government’s oppression.