We've just released a new alpha release that has the first pass at our Equihash PoW implementation and the Founder's Reward mechanics. This is the first release that those interested in mining can really start to dig into, but beware that the current implementation isn't optimized and the current algorithm parameters aren't what we'll use in the 1.0 launch. (The blog post links to tickets for these followup improvements.)
More details are on our blog: https://z.cash/blog/new-alpha-release-equihash-and-founders-reward.html
Please feel welcome to post issues, concerns, feedback here!