Seems more logical to me than going from English again, so you can practice both. I'm using it as a next step after Introduction to Japanese (memrise.com/course/12/introduction-to-japanese/), before going on to vocab lists that contain katakana. Full audio. Anyway, good luck!
Course forum: https://community.memrise.com/t/course-forum-katakana-from-hiragana-by-weirdfatty/932
Welcome to Memrise!
Join millions of people who are already learning for free on Memrise! It’s fast, it’s fun and it’s mind-bogglingly effective.