You probably want this part, instead of the other, which sells in qty = 1800.
http://www.digikey.com/product-detail/en/N25Q128A13ESE40E/557-1562-ND/3874288
108Mhz is the max clock speed, and they usually run at slower speeds. Also, notice these
are 3.3V parts, so you'll need level-shifters to interface with 5V Arduino. Most Flash chips
I've seen are 3.3V, and not 5V, devices.
Also, the reason they're spec'ed in Mbits instead of MBytes is because all serial memory
are usually spec'ed that way.
Also, Mbits isn't speed, Mbits/sec is speed. Don't know about formatting as SD.