In chronological order:
May 19, 2013: Universal and affordable computational integrity
Given at Bitcoin 2013 by Eli Ben-Sasson (video).
The talk covers, at high level, the idea of "succinct" (short and easy-to-verify) proofs.
January 13, 2014: Anonymizing Cryptocurrencies: How to make Bitcoin Anonymous
Given at the 2014 Real-World Cryptography Workshop by Matthew Green (video).
The talk covers Zerocoin and (an early version of) Zerocash.
February 27, 2014: Zerocash: Zerocoin meets SCIPR Lab
Given at the 2014 Bitcoin Israel Conference by Eli Ben-Sasson (video).
The talk covers the Zerocash construction.
March 26, 2014: Zerocash: מטבע דיגיטלי משמר פרטיות (Privacy-Preserving Digital Currency)
Given at the 2014 Israel Science Day by Eran Tromer.
A brief overview of Zerocash, in Hebrew, to the general public.
April 22, 2014: Zerocash: Zerocoin meets SCIPR Lab
Given at the Israel Bitcoin Foundation by Eli Ben-Sasson (video).
The talk covers the Zerocash construction.
May 18, 2014: Zerocash: Decentralized Anonymous Payments
Given at the Silicon Valley Ethereum Meetup by Eran Tromer (video).
The talk covers the Zerocash construction, followed by an extensive technical discussion.
May 20, 2014: Zerocash: Decentralized Anonymous Payments from Bitcoin
Given at the 2014 IEEE Symposium on Security and Privacy by Eran Tromer. (slides: pptx pdf)
The talk covers the motivation for Zerocash and the main ideas in its construction.
November 13, 2014: Zerocash: improving Bitcoin using SNARKs
Given at the The First Greater Tel Aviv Area Cryptography Symposium by Eran Tromer. (video)
The talk covers the motivation for Zerocash and the main ideas in its construction.
March 8, 2015: Zerocash
Given at the MIT Bitcoin Expo 2015 by Madars Virza. (video)
The talk covers the motivation for Zerocash and the main ideas in its construction.
May 25, 2014: Israeli national radio station Reshet Bet, "שש עם ענת דולב" (recording, starts at 14:32)
Interview with Eran Tromer on Zerocash (in Hebrew), describing the system to the general public.
May 14, 2014: NPR Science Friday, This Cryptocurrency Could Be an Answer to Bitcoin's Privacy Problems (article).