I found one company, The Mate Factor, that sells Yerba Mate green tea. The tea is USDA organic certified and is actually made from the yerba mate plant (this plant is an evergreen from the Holly family that grows in the subtropical forests of South America). Yerba Mate (Pronounced Mah-Tay) is similar to Green Tea yet higher in nutritional value. According to some studies, Yerba Mate contains 27% more active nutritional compounds than green tea. The Mate Factor company also sells other teas.
So, how does it taste? I enjoy the aroma from this tea. It reminds me of a blend between jasmine and green tea. It has a very faint flora taste (with no bitter aftertaste).