What are the best resources to learn about yogacara buddhism? Online resources, books, anything would be fine.
One of the best introductory books I've found is called Living Yogacara. It's fairly straightforward and reasonably accessible. Another book that I found helpful is entitled Context and Dialogue. While this is a comparative study of mutliple notions of the unconscious, I found the author's explanation of Yogacara (specifically the alaya vijnana) pretty thorough and very easy to follow. Past that, you'll need to get into the writings of Asanga and Vasubandhu. These are not easy.
Of course, the best way to explore yogacara is to practice it. Rinzai Zen is probably the last existent school that makes yogacara notions of the mind its centerpiece.