About time Amazon started to list these cards. Hopefully the 32gb and 8gb will be listed, too. Unless it already is listed, but it's difficult to find like the rest of these cards. Feh.
If anyone knows where the 32gb/8gb memory card preorder pages are, feel free to post it here or any of the Vita system forums. :)
Here's the 4gb preorder, btw. :)
4GB PlayStation Vita Memory Card